,,united ,,states ,,department ,,of ,,agriculture ,,bulletin ,no4 #ajia ,also ,technical ,bulletin ,no4 #a of the ,agricultural ,experiment ,station ,university of ,arizona ,washington1 ,d4 ,c4 ,,professional ,,paper ,september #ac1 #aibb ,,life ,,history ,,of ,,the ,,kangaroo ,,rat ,dipodomys spectabilis spectabilis ,merriam ,,by ,,charles ,t4 ,,vorhies1 ,entomologist ,agricultural ,experiment ,station1 ,university of ,arizona2 and ,,walter ,p4 ,,taylor1 ,assistant ,biologist ,bureau of ,biological ,survey1 ,u4 ,s4 ,department of ,agriculture ,,contents ,importance of ,rodent ,groups #a ,identification #c ,description #e ,occurrence #g ,habits #i ,food and ,storage #ah ,burrow ,systems1 or ,dens #bh ,commensals and ,enemies #cc ,abundance #cf ,economic ,considerations #cf ,summary #ch ,bibliography #dj ,illustration ,,washington ,,government ,,printing ,,office #aibb ,illustration3 ,,plate ,i4--,banner-tailed ,kangaroo ,rat 7,dipodomys spectabilis spectabilis ,merriam74 ,from ,dipodomys merriami ,mearns and subspecies1 which occur over much of its range1 this form is easily distinguished by its larger size and the conspicuous white brush on the tail4 ,,united ,,states ,,department ,,of ,,agriculture ,,bulletin ,no4 #ajia ,also ,technical ,bulletin ,no4 #a of the ,agricultural ,experiment ,station1 ,university of ,arizona ,washington1 ,d4 ,c4 ,,professional ,,paper ,september1 #aibb ,,life ,,history ,,of ,,the ,,kangaroo ,,rat1 ,dipodomys spectabilis spectabilis ,merriam4 ,by ,,charles ,t4 ,,vorhies1 ,entomologist1 ,agricultural ,experiment ,station1 ,university of ,arizona2 and ,,walter ,p4 ,,taylor1 ,assistant ,biologist1 ,bureau of ,biological ,survey1 ,u4 ,s4 ,department of ,agriculture4 ,,contents4 ,page ,importance of rodent groups #a ,investigational methods #b ,identification #c ,description #e ,general characters #e ,color #f ,oil gland #f ,measurements and weights #g ,occurrence #g ,general distribution #g ,habitat #g ,habits #i ,evidence of presence #i ,mounds #i ,runways and tracks #aj ,signals #aa ,voice #ab ,daily and seasonal activity #ab ,pugnacity and sociability #ac ,sense developments #ad ,movements and attitudes #ae ,storing habits #ae ,breeding habits #af ,food and storage #ah ,burrow systems1 or dens #bh ,commensals and enemies #cc ,commensals #cc ,natural checks #cd ,parasites #ce ,abundance #cf ,economic considerations #cf ,control #cg ,summary #ch ,bibliography #dj ,,note4--,this bulletin1 a joint contribution of the ,bureau of ,biological ,survey and the ,arizona ,agricultural ,experiment ,station1 contains a summary of the results of investigations of the relation of a subspecies of kangaroo rat to the carrying capacity of the open ranges1 being one phase of a general study of the life histories of rodent groups as they affect agriculture1 forestry1 and grazing4 ,,importance ,,of ,,rodent ,,groups4 ,as the serious character of the depredations by harmful rodents is recognized1 ,state1 ,federal1 and private expenditures for their control increase year by year4 ,these depredations include not only the attacks by introduced rats and mice on food materials stored in granaries1 warehouses1 commercial establishments1 docks1 and private houses1 but also1 particularly in the ,western ,states1 the ravages of several groups of native ground squirrels and other noxious rodents in grain and certain other field crops4 ,nor is this all1 for it has been found that such rodents as prairie dogs1 pocket gophers1 marmots1 ground squirrels1 and rabbits take appreciable and serious toll of the forage on the open grazing range2 in fact1 that they reduce the carrying capacity of the range to such an extent that expenditures for control measures are amply justified4 ,current estimates place the loss of goods due to rats and mice in warehouses and stores throughout the ,united ,states at no less than #bjj1jjj1jjj annually1 and damage to the carrying capacity of the open range and to cultivated crops generally by native rodents in the ,western ,states at #cjj1jjj1jjj additional2 added together1 we have an impressive total from depredations of rodents4 ,the distribution and life habits of rodents and the general consideration of their relation to agriculture1 forestry1 and grazing1 with special reference to the carrying capacity of stock ranges1 is a subject that has received attention for many years from the ,biological ,survey of the ,united ,states ,department of ,agriculture4 ,as a result of the investigations conducted much has been learned concerning the economic status of most of the more important groups1 and the knowledge already gained forms the basis of the extensive rodent-control work already in progress1 and in which many ,states are cooperating with the bureau4 ,if the work is to be prosecuted intelligently and the fullest measure of success achieved1 it is essential that the consideration largely of groups as a whole be supplemented by more exhaustive treatment of the life histories of individual species and of their place in the biological complex4 ,the present report is based upon investigations1 chiefly in ,arizona1 of the life history1 habits1 and economic status of the banner-tailed kangaroo rat1 ,dipodomys spectabilis spectabilis ,merriam 7,pl4 ,i74 ,,investigational ,,methods4 ,some #ah years ago 7in #aijc7 a tract of land #di4b square miles in area on the ,coronado ,national ,forest near the ,santa ,rita ,mountains1 ,pima ,county1 southern ,arizona1 was closed to grazing by arrangement between the ,forest ,service and the ,agricultural ,experiment ,station of the ,university of ,arizona4 ,since that time another small tract of nearly a section has been inclosed 7,griffiths1 #aiaj1 #ga74 ,this total area of approximately #ej square miles is known as the ,united ,states ,range ,reserve1 and is being devoted to a study of grazing conditions in this section and to working out the best methods of administering the range 7,pl4 ,,ii1 ,fig4 #a74 ,for some years an intensive study of the forage and other vegetative conditions of this area has been made1 the permanent vegetation quadrat1 as proposed by ,dr4 ,f4 ,e4 ,clements 7#aije1 #afa-age71 being largely utilized4 ,during the autumn of #aiag representatives of the ,carnegie ,institution and the ,arizona ,agricultural ,experiment ,station visited the ,reserve and were impressed with the evidence of rodent damage to the grass cover4 ,the most conspicuous appearance of damage was noted about the habitations of the banner-tailed kangaroo rat 7,dipodomys spectabilis spectabilis ,merriam71 although it was observed also that jack rabbits of two species 7,lepus californicus eremicus ,allen and ,l4 alleni alleni ,mearns71 which were very abundant in some portions of the reserve1 were apparently affecting adversely the forage conditions in particular localities4 ,accordingly1 the ,biological ,survey1 the ,agricultural ,experiment ,station of the ,university of ,arizona1 the ,carnegie ,institution of ,washington1 and the ,u4 ,s4 ,forest ,service have undertaken a study of the relation of the more important rodents to the forage crop of the ,range ,reserve in ,arizona4 ,the present paper is a first step in this larger investigation4#b ,in this work the authors have made no attempt to deal with the taxonomic side of the kangaroo rat problem4 ,it is not unlikely that intensive studies will show that the form now known as ,dipodomys spectabilis spectabilis is made up of a number of local variants1 some of them perhaps worthy of recognition as additional subspecies4 ,but it is felt that the conclusions here reached will be little1 if at all1 affected by such developments4 ,color descriptions are based on ,ridgway's ,color ,standards and ,color ,nomenclature published in #aiab4 ,footnote #a3 ,references in parentheses are to the ,bibliography1 p4 #dj 7the last figure being to the page of the publication74 ,references to authorities where no citation of literature is appended relate for the most part to manuscript notes in the files of the ,biological ,survey or the ,university of ,arizona ,agricultural ,experiment ,station4 ,footnote #b3 ,in addition to assistance rendered by officials of the ,biological ,survey and the ,university of ,arizona1 which is hereby acknowledged1 the authors are indebted to the following persons for helpful suggestions and assistance3 ,g4 ,s4 ,miller and ,j4 ,w4 ,gidley1 of the ,u4 ,s4 ,national ,museum2 ,dr4 ,frederic ,e4 ,clements and ,gorm ,loftfield1 of the ,carnegie ,institution2 ,morgan ,hebard1 of the ,academy of ,natural ,sciences of ,philadelphia2 ,james ,t4 ,jardine and ,r4 ,l4 ,hensel1 both formerly connected with the ,u4 ,s4 ,forest ,service2 and ,r4 ,r4 ,hill1 of the ,forest ,service4 ,they are also indebted to ,william ,nicholson1 of ,continental1 ,ariz41 for many courtesies extended in connection with work on the ,reserve4 ,,identification4 ,there are only three groups of mammals in the ,southwest having external cheek pouches4 ,these are 7a7 the pocket gophers 7,geomyid71 which have strong fore feet1 relatively weak hind feet1 and short tail1 as compared with weak fore feet1 relatively strong hind feet1 and long tail in the other two2 7b7 the pocket mice 7,perognathus71 which are considerably smaller than the kangaroo rats and lack the conspicuous white hip stripe possessed by all the latter2 and 7c7 the kangaroo rats 7,dipodomys74 ,illustration3 ,,fig4 #a4--,range1 east of the ,colorado ,river1 of ,dipodomys spectabilis spectabilis compared with that of ,dipodomys merriami4 ,cross hatching indicates area of overlapping of the two forms4 ,the range of ,dipodomys deserti1 not shown on the map1 is west of that of spectabilis1 and so far as known the two do not overlap4 ,dipodomys spectabilis spectabilis ,merriam requires comparison with three other forms of kangaroo rats in the same general region1 namely1 ,d4 deserti ,stephens1 of approximately the same size1 and ,d4 merriami ,mearns and ,d4 ordii ,woodhouse1 the last two of decidedly smaller size4 ,the range of deserti lies principally to the west of that of spectabilis1 and the two do not1 so far as known1 overlap4 ,on the other hand1 merriami and ordii1 and subspecies1 occur over a large part of the range of spectabilis1 living in very close proximity to its burrows2 merriami is even suspected of pillaging the stores of spectabilis4 ,the range of merriami1 however1 is much more extensive than that of spectabilis 7,fig4 #a71 which argues against a definite ecological dependence or relationship4 ,separation of the four forms mentioned may be easily accomplished by the following key3 ,key to ,species of ,dipodomys in ,arizona4 a#a4 ,size much larger 7hind foot and greatest length of skull more than #db millimeters72 tail tipped with white4 b#a4 ,upper parts dark brownish buffy2 tail dark brownish or blackish with more sharply contrasted white tip2 interparietal broader1 distinctly separating mastoids 7range in ,arizona mainly southeastern part7 ,dipodomys spectabilis4 b#b4 ,upper parts light ochraceous-buffy2 tail pale brownish with less sharply contrasted white tip2 interparietal narrower1 reduced to mere spicule between mastoids 7range in ,arizona mainly southwestern part7 ,dipodomys deserti4 a#b4 ,size much smaller 7hind foot and greatest length of skull less than #db millimeters72 tail not tipped with white4 b#a4 ,hind foot with four toes ,dipodomys merriami4 b#b4 ,hind foot with five toes ,dipodomys ordii4 ,on account of the small size1 merriami and ordii do not require detailed color comparison with the other two4 ,the general color of the upperparts of spectabilis is much darker than that of deserti2 whereas spectabilis is ochraceous-buff or light ochraceous-buff grizzled with blackish1 deserti is near pale ochraceous-buff and lacks the blackish4 ,the color of the upperparts alone amply suffices to distinguish spectabilis and deserti2 but the different coloration of the tail is the most obvious diagnostic feature4 ,the near black of the middle portion of the tail1 the conspicuous white side stripes1 and the pure white tip make the tail of spectabilis stand in rather vivid contrast to the pale-brown and whitish tail of deserti4 ,the dens of the two larger species of ,dipodomys--spectabilis and deserti--can be distinguished at a glance from those of the two smaller--merriami and ordii--by the fact that the mounds of the former are usually of considerable size and the burrow mouths are of greater diameter4 ,on the ,range ,reserve merriami erects no mounds1 but excavates its burrows in the open or at the base of ,prosopis1 ,lycium1 or other brush4 ,the mounds of spectabilis are higher than those of deserti1 the entrances are larger1 and they are located in harder soil 7,pl4 ,,iii1 ,fig4 #a74 ,the dens of deserti are usually more extensive in surface area than those of spectabilis1 and have a greater number of openings 7,pl4 ,,iii1 ,fig4 #b74 ,illustration3 ,,plate ,,ii4 ,,fig4 #a4--,,winter ,,view ,,of ,,area ,,inhabited ,,by ,,kangaroo ,,rats4 ,a water-hole scene on the ,u4 ,s4 ,range ,reserve at the base of the ,santa ,rita ,mountains1 ,ariz41 where cooperative investigations are being conducted to ascertain the relation of rodents to forage4 ,this is typical of a large section of country occupied by ,dipodomys spectabilis spectabilis and ,dipodomys merriami4 ,the brush is mesquite 7,prosopis71 cat's-claw 7,acacia71 and paloverde 7,cercidium74 ,illustration3 ,,plate ,,ii4 ,,fig4 #b4--,,kangaroo ,,rat ,,country ,,following ,,summer ,,drought4 ,an area of the ,u4 ,s4 ,range ,reserve in the autumn of #aiah1 showing the result of failure of summer rains4 ,such a condition is critical not only for the stockmen but also for kangaroo rats and other desert rodents1 and results in competition between them as to which shall benefit by what the range has to offer4 ,illustration3 ,,plate ,,iii4 ,,fig4 #a4--,,kangaroo ,,rat ,,mound 7,,dipodomys ,s4 ,,spectabilis74 ,typical ,dipodomys s4 spectabilis mound on the ,range ,reserve1 under shelter of desert hackberry 7,celtis pallida74 ,most dens on the reserve are located in the shelter of brush plants1 the more important being mesquite 7,prosopis velutina71 cat's-claw 7,acacia spp471 and the desert hackberry4 7,see also ,pl4 ,,viii ,fig4 #b47 ,illustration3 ,,plate ,,iii4 ,,fig4 #b4--,,kangaroo ,,rat ,,mound 7,,dipodomys ,,deserti74 ,den of ,dipodomys deserti deserti1 showing typical wide1 low mound with numerous entrance holes4 ,this species excavates its den in soft1 sandy soil4 ,the tree is a species of ,dalea4 ,,description4 ,,general ,,characters4 ,size large2 ears moderate1 ear from crown 7taken in dry skin7 #i or #aj millimeters2 eyes prominent2 whiskers long and sensitive2 fore feet short and weak2 hind feet long and powerful1 provided with four well-developed toes2 tail very long1 usually #cj to #dj per cent longer than the body4 ,cranium triangular1 the occiput forming the base and the point of the nose the apex of the triangle1 much flattened1 auditory and particularly mastoid bullae conspicuously inflated4 ,,color4 ,general color above1 brownish buffy1 varying in some specimens to lighter buffy tints1 grizzled with black2 oblique hip stripes white2 tail with dark-brown or blackish stripes above and below1 running into blackish about halfway between base and tip1 and with two lateral side stripes of white to a point about halfway back2 tail tipped with pure white for about #dj millimeters 7,pl4 ,i74 ,underparts white1 hairs white to bases1 with some plumbeous and buffy hairs about base of tail2 fore legs and fore feet white all around2 hind legs like back1 brown above1 hairs with gray bases1 becoming blackish 7fuscous-black or chtura-black7 about ankles1 hairs on under side white to bases2 hind feet white above1 dark-brown or blackish 7near fuscous7 below4 ,color variations in a series of #ab specimens from the type locality and points widely scattered through the range of spectabilis consist in minor modifications of the degree of coloration1 length of white tip of tail1 and length of white lateral tail stripes4 ,in general the color pattern and characters are remarkably uniform4 ,young specimens1 while exhibiting the color pattern and general color of adults1 are conspicuously less brown1 and more grayish4 ,there appears to be little variation in color with season4 ,in the series at hand1 most specimens taken during the fall1 winter1 and spring are very slightly browner than those of summer1 suggesting that the fresh pelage following the fall molt is a little brighter than is the pelage after being worn all winter and into the following summer4 ,but at most the difference is slight4 ,,oil ,,gland4 ,upon separating the hairs of the middle region of the back about a third of the distance between the ears and the rump1 one uncovers a prominent gland1 elliptical in outline1 with long axis longitudinal and about #i millimeters in length4 ,the gland presents a roughened and granular appearance1 and fewer hairs grow upon it than elsewhere on the back4 ,the hairs in the vicinity are frequently matted1 as if with a secretion4 ,in worn stage of pelage the gland may be visible from above without separating the hairs4 ,bailey has suggested that this functions as an oil gland for dressing the fur1 and our observations bear out this view4 ,kangaroo rats kept in captivity without earth or sand soon come to have a bedraggled appearance1 as if the pelage were moist4 ,when supplied with fine1 dusty sand1 they soon recover their normal sleek appearance4 ,apparently the former condition is due to an excess of oil1 the latter to the absorption of the excess in a dust bath4 ,the oil is doubtless an important adjunct to the preservation of the skin and hair amid the dusty surroundings in which the animal lives4 ,,measurements ,,and ,,weights4 ,external measurements include3 ,total length1 from tip of nose to tip of tail without hairs1 measured before skinning2 tail vertebr1 length of tail from point in angle when tail is bent at right angles to body to tip of tail without hairs2 and hind foot1 from heel to tip of longest claw4 ,the following are measurements of a series from the ,u4 ,s4 ,range ,reserve3 ,transcriber note3 ,next line was corrected per erratum4 ,the original text was of the following paragraph 7,averages for #ag adult females3 ,total length1 #cbf4d millimeters74 ,average measurements of #cj adult specimens of both sexes3 ,total length1 #cbf4b millimeters 7#cdi-caj72 tail vertebr1 #ahh4d 7#bjh-ahj72 hind foot1 #di4e 7#ea-dg72 the average weight of #bi adult specimens of both sexes was #aad4e grams 7#aca4i-ih4j74 ,averages for #ag adult females3 ,total length1 #cbf4d millimeters 7#cdi-caj72 tail vertebr1 #ahh4h 7#bjh-agi72 weight 7#af individuals71 #aac4g 7#aca4i-ih4j72 excluding pregnant females1 #ac individuals averaged #aab4i grams 7#aca4i-ih4j74 ,averages for #ac adult males3 ,total length1 #cbf millimeters 7#cde-caa72 tail vertebr1 #ahg4h 7#bjb-afh72 weight1 #aaf4h grams 7#abi-ajj74 ,there appears to be no significant difference in the measurements and weights of males and females1 with the possible exception of the comparison of adult males and adult nonpregnant females4 ,,occurrence4 ,,general ,,distribution4 ,dipodomys spectabilis spectabilis is found in southeastern ,arizona1 in northwestern1 central1 and southern ,new ,mexico1 in extreme western ,texas1 in northern ,sonora1 and in northern and central ,chihuahua 7,fig4 #a74 ,a subspecies1 ,d4 s4 cratodon ,merriam1 has been described from ,chicalote1 ,aguas ,calientes1 ,mexico1 the geographic range of which lies in central ,mexico in portions of the ,states of ,zacatecas1 ,san ,luis ,potosi1 and ,aguas ,calientes4 ,,habitat4 ,in the ,tucson region spectabilis is typically a resident of the ,lower ,sonoran ,zone4 ,this is perhaps the principal zone inhabited over its entire range1 but the animal is often found in the ,upper ,sonoran also1 and in the ,gallina ,mountains of ,new ,mexico ,hollister found it invading the yellow pine ,transition where the soil was dry and sandy and the pine woods of open character4 ,the same observer found it common in grassy and weed-grown parks among the large junipers1 pinyons1 and scattering yellow pines of the ,bear ,spring ,mountains1 ,n4 ,mex4 ,bailey calls attention to the fact that the animal apparently does not inhabit the lower half of the ,lower ,sonoran ,zone1 as it extends neither into the ,rio ,grande ,valley of ,texas nor the ,gila ,valley of ,arizona4 ,in extreme western ,texas it is common at the upper edge of the arid ,lower ,sonoran ,zone1 and in this region does not enter the ,upper ,sonoran to any extent4 ,in ,july1 #aiad1 ,goldman found this kangaroo rat common on the plain at #d1fjj feet altitude1 near ,bonita1 ,graham ,county1 ,ariz41 and noted a few as high as #e1jjj feet altitude on the warm southwestern slopes of the ,graham ,mountains1 near ,fort ,grant4 ,apparently spectabilis reaches its upper altitude limit in the ,burro ,mountains1 ,n4 ,mex41 where ,bailey has found it sparingly on warm slopes up to #e1gjj feet1 and at the western base of the ,sandia ,mountains1 east of ,albuquerque1 ,n4 ,mex41 where dens occur at approximately #f1jjj feet4 ,about ,tucson it is undoubtedly more common in the somewhat higher portions of the ,lower ,sonoran ,zone1 above the ,covillea association1 than elsewhere 7,pl4 ,,iv1 ,figs4 #a and #b74 ,a few scattered dens are to be seen in the ,covillea belt1 but as one rises to altitudes of #c1ejj to #d1jjj feet1 and the ,covillea is replaced by the cat's-claws 7,acacia sp4 and ,mimosa sp47 and scattered mesquite 7,prosopis71 with the ,opuntia becoming less abundant1 kangaroo rat mounds come more and more in evidence4 ,here is to be found the principal grass growth supporting the grazing industry1 and the presence of a more luxuriant grass flora is probably an important factor in the greater abundance of kangaroo rats1 both spectabilis and merriami4 ,in this generally preferred environment the desert hackberry 7,celtis pallida7 is one of the most conspicuous shrubs2 clumps of this species are commonly accompanied by kangaroo rat mounds4 ,in order to ascertain whether the banner-tailed kangaroo rat has any marked preference for building its mounds under ,celtis or some other particular plant1 all the observable mounds were counted in a strip about #bj rods wide and approximately #d miles long1 an area of approximately #afj acres1 particular note being taken of the kind of shrub under which each mound was located4 ,of #cjj mounds in this area1 #if were under ,prosopis1 #ie under ,acacia1 #fe under ,celtis1 #aa under ,lycium1 #ca in the open1 #a about a cholla cactus 7,opuntia spinosior71 and #a about a prickly pear 7,opuntia sp474 ,there is apparently no strongly marked preference for any single species of plant4 ,while both desert hackberry and the cat's-claws afford a better protection than mesquite--since cattle more often seek shade under the latter1 and in so doing frequently trample the mounds severely--it appears that the general protection of a tree or shrub of some sort is sought by kangaroo rats1 rather than the specific protection of the thickest or thorniest species4 ,the following records indicate particular habitat preferences of spectabilis as noted at different points in its range3 ,occurs on open bare knolls exposed to winds1 also on gravelly places at lower edge of foothills 7,franklin ,mountains1 ,tex41 ,gaut72 here and there over the barest and hardest of the gravelly mesas 7,bailey1 ,tex41 #aije1 #adg72 on open creosote-bush and giant-cactus desert 7,tucson1 ,ariz41 ,vorhies and ,taylor72 on firm1 gravelly1 or even rocky soil on the grassy bajada land along the northwest base of the mountains1 either in the open or under ,celtis1 ,prosopis1 ,lycium1 ,acacia greggii1 or other brush 7,santa ,rita ,mountains1 ,ariz41 ,vorhies and ,taylor72 mounds usually thrown up around a bunch of cactus or mesquite brush 7,magdalena1 ,sonora1 ,bailey72 in heavy soil 7,ajo1 ,ariz41 ,a4 ,b4 ,howell72 loamy soil 7,gunsight1 ,ariz41 ,a4 ,b4 ,howell72 in mesa where not too stony 7,magdalena1 ,sonora1 ,bailey72 grassy plain 7,gallego1 ,chihuahua1 ,nelson72 in open valley and high open plains 7,santa ,rosa1 ,n4 ,mex41 ,bailey72 in grassy and weed-grown parks among the larger junipers1 pinyons1 and scattering yellow pines 7,bear ,spring ,mountains1 ,n4 ,mex41 ,hollister72 on sand-dune strip 7east side of ,pecos ,river1 #ae miles northeast of ,roswell1 ,n4 ,mex41 ,bailey72 among ,ephedra patches 7,san ,juan ,valley1 ,n4 ,mex41 ,birdseye72 in open sandy soil along dry wash 7,rio ,alamosa1 ,n4 ,mex41 ,goldman72 on sides and crests of bare1 stony hills 7,mesa ,jumanes1 ,n4 ,mex41 ,gaut72 in open1 arid part of the valley and stony mesas 7,carlsbad and ,pecos ,valley1 ,n4 ,mex41 ,bailey72 about the edges of the plains of ,san ,augustine and the foothills of the ,datil and ,gallina ,mountains1 and in the ,transition ,zone yellow-pine forest of the ,gallina ,mountains 7,datil region1 ,n4 ,mex41 ,hollister72 on hard limy ridges 7,monahans1 ,tex41 ,cary74 ,a4 ,brazier ,howell notes that spectabilis occurs in harder soil than does deserti4 ,this observation is confirmed by others1 and seems to afford a conspicuous habitat difference between the two1 for deserti is typically an animal of the shifting aeolian sands4 ,usually1 as on the ,range ,reserve1 the rodents are widely distributed over a considerable area4 ,occasionally1 as in the vicinity of ,rio ,alamosa1 ,n4 ,mex41 as reported by ,goldman1 they occur only in small colonies4 ,illustration3 ,,plate ,,iv4 ,,fig4 #a4--,,range ,,conditions ,,favoring ,,kangaroo ,,rats4 ,view on higher portion of ,range ,reserve1 showing type of country where ,dipodomys s4 spectabilis is most abundant4 ,good growth of grama and needle grasses in ,october1 following summer growth and before grazing off by cattle and rodents4 ,illustration3 ,,plate ,,iv4 ,,fig4 #b4--,,range ,,conditions ,,less ,,favorable ,,to ,,kangaroo ,,rats4 ,view on lower portion of ,range ,reserve1 where ,dipodomys s4 spectabilis is less abundant4 ,vegetation consists principally of ,lycium1 mesquite1 rabbit brush1 and cactus1 there being very little grass4 ,,habits4 ,,evidence ,,of ,,presence4 ,,mounds4 ,one traveling over territory thickly occupied by the banner-tailed kangaroo rat is certain to note the numerous and conspicuous mounds so characteristic of the species1 particularly if the region is of the savannah type1 grassy rather than brushy4 ,these low1 rounded mounds occupy an area of several feet in diameter1 and rise to varying heights above the general surface of the surrounding soil1 the height depending rather more upon the character of the soil and the location of the mound as to exposure or protection than upon the area occupied by the burrow system which lies within and is the reason for the mound4 ,a den in sandy soil in the open may be of maximum size in area occupied and yet scarcely present the appearance of a mound in any sense1 due probably both to the fact that the sandy soil will not heap up to such a height over a honeycomb of tunnels as will a firmer or rocky soil1 and also to its greater exposure to the leveling action of rains and the trampling of animals4 ,these mounds are in themselves large enough to attract some attention1 but their conspicuousness is enhanced by the fact that they are more or less completely denuded of vegetation and are the centers of cleared areas often as much as #cj feet in diameter 7,pl4 ,v1 ,fig4 #a72 and further that from #c to #ab large dark openings loom up in every mound4 ,the larger openings are of such size as to suggest the presence of a much larger animal than actually inhabits the mound4 ,add to the above the fact that the traveler by day never sees the mound builder1 and we have the chief reasons why curiosity is so often aroused by these habitations4 ,on the ,range ,reserve the mounds are usually rendered conspicuous by the absence of small vegetation1 but ,nelson writes that in the vicinity of ,gallego1 ,chihuahua1 they can be readily distinguished at a distance because of a growth of weeds and small bushes over their summits1 which overtop the grass4 ,in the vicinity of ,albuquerque1 ,n4 ,mex41 ,bailey reports 7and this was recently confirmed by ,vorhies7 that the mounds about the holes of spectabilis are often hardly noticeable4 ,hollister writes that in the yellow-pine forests of the ,gallina ,mountains the burrows are usually under the trunk of some fallen pine1 both sides of it in some cases being taken up with holes1 there being some eight or ten entrances along each side1 the burrows extending into the ground beneath the log4 ,in the vicinity of ,blanco1 ,n4 ,mex41 ,birdseye says that occasionally spectabilis makes typical dens but more often lives in old prairie-dog holes 7,cynomys71 or in holes which look more like those of ,d4 ordii4 ,,runways ,,and ,,tracks4 ,still other features add to the interest in the dwelling places of spectabilis4 ,radiating in various directions from some of the openings of the mounds well-used runways are to be seen1 some of them fading out in the surrounding vegetation1 but others extending #cj1 #dj1 or even #ej or more yards to neighboring burrows or mounds 7,pl4 ,v1 ,fig4 #b2 ,pl4 ,,vi1 ,fig4 #a74 ,these runways and the entrances to the mounds are well worn1 showing that the inhabitants are at home and are at some time of day very active4 ,the worn paths become most conspicuous in the autumnal harvest season1 when they stand out in strong contrast to surrounding grass4 ,one usually finds not far distant from the main habitation one or more smaller burrows1 each with from one to three typical openings1 connected by the trail or runway system with the central den1 and these we have called subsidiary burrows 7,pl4 ,,vi1 ,fig4 #b74 ,these will be again referred to in discussing the detailed plan of the entire shelter system4 ,examination of the runways and of the denuded area about a mound discloses an abundance of almost indecipherable tracks4 ,the dust or sand is ordinarily much too dry and shifting to record clear footprints1 and there are no opportunities to see footprints of this species recorded in good impressionable soil4 ,very characteristic traces of kangaroo rats may be readily observed in the dust about the mounds1 however1 and these are long1 narrow1 sometimes curving1 furrows made by the long tails as the animals whisk about their work or play4 ,illustration3 ,,plate ,v4 ,,fig4 #a4--;,,clearing ,,about ,a ,,mound4 ,a typical clearing about a mound of ,dipodomys s4 spectabilis1 showing the autumnal denudation of the mound and surrounding areas4 ,in this instance about #cj feet in diameter4 ,illustration3 ,,plate ,v4 ,,fig4 #b4--,,mound ,,and ,,runways4 ,a small mound of ,dipodomys s4 spectabilis in early autumn1 showing runways radiating from the den4 ,evidences of activity may be noted in and about the surface of the mound4 ,illustration3 ,,plate ,,vi4 ,,fig4 #a4--,,runway ,,of ,,dipodomys ,s4 ,,spectabilis4 ,well-traveled path leading from the main den1 in the foreground1 to a subsidiary burrow 7see ,fig4 #b1 below71 about #cj feet distant1 at apparent end of runway4 ,illustration3 ,,plate ,,vi4 ,,fig4 #b4--,,subsidiary ,,burrow ,,of ,,dipodomys ,s4 ,,spectabilis4 ,located at the end of the #cj-;foot runway shown in ,figure #a1 above4 ,this has three openings1 two in the foreground and the third a little to the rear and indicated by an arrow4 ,,signals4 ,if a scratching or tapping sound be made at the mouth of a burrow1 even in the daytime1 one is likely to hear a muffled tapping in response1 and this may at times be heard while one is engaged in excavating a mound4 ,it has a chirring or fluttering quality1 described by ,fisher as resembling the noise of a quail flying4 ,bailey 7#aije1 #adh7 is of the opinion that it is used as a signal of alarm1 call note1 or challenge1 a view which the present authors believe to be correct4 ,during the winter of #aibj-ba1 however1 both ,bailey and ,vorhies discovered that this sound1 or a very similar one1 is made by the rapid action of the forefeet in digging4 ,on one occasion in the laboratory the sound was given by one of a pair and was responded to at once by the other1 the two being in separate but contiguous cages4 ,this observation1 however1 could not be repeated4 7,vorhies ,,ms47 ,one evening1 while working in the vicinity of the ,burro ,mountains1 ,n4 ,mex41 ,goldman heard a kangaroo rat near camp making this thumping noise4 ,taking a lantern1 he approached the den1 very cautiously1 until within #aj feet4 ,the kangaroo rat was just outside the entrance of one of its burrows1 and though moving about more or less restlessly at first showed little fear1 and kept up the thumping or drumming at intervals4 ,when making the noise the animal was standing with the forefeet on the ground and the tail lying extended4 ,the noise seemed to be made with the hind feet only1 and the vibration of the feet could be seen4 ,the tapping was kept up for a second or two at a time1 the sounds coming close together and being repeated rhythmically after a very short interval1 suggesting the distant galloping of a horse4 ,after continuing in this way for a short time1 the animal turned quickly about1 with its head in the opposite direction1 and began tapping4 ,it appeared to pay little attention to the light1 but finally gave a sudden bound and entered one of its holes about #d feet from the one in front of which it had been standing4 ,vorhies has repeatedly noted when watching for the appearance of a kangaroo rat at night that this sound invariably precedes the rodent's first emergence into the open1 and often its appearance after an alarm1 though when the storage season has begun and the kangaroo rat is carrying loads of grass heads or other material into its den1 it regularly comes out without preliminary signaling4 ,vorhies has also observed it making the sound while on top of the mound1 and certainly not digging1 but was unable to see how it was made4 ,,voice4 ,no data concerning any call notes or sounds other than those described above are at hand1 with the following exception3 ,price 7in ,allen1 #ahie1 #bac71 who studied the habits of the animal in the moonlight1 at ,willcox1 ,ariz41 says that a low chuckle was uttered at intervals2 and ,vorhies has had one captive female that would repeatedly utter a similar chuckle in a peevish manner when disturbed by day1 and one captive male which1 when teased into a state of anger and excitement1 would squeal much like a cornered house rat4 ,vorhies has spent many moonlight hours observing kangaroo rats1 but without ever hearing a vocal sound uttered by free individuals4 ,,daily ,,and ,,seasonal ,,activity4 ,the kangaroo rat is strictly nocturnal4 ,an observer watching patiently by a den in the evening for the animal's first appearance is not rewarded until darkness has fallen completely1 and unless the moon is shining the animal can hardly be seen4 ,were it not for the white tail-brush of spectabilis and its white belly when upright on the hind legs and tail1 one could not as a rule see the animal at all when it makes its first evening appearance4 ,with the first streak of dawn activity usually ceases completely and much more abruptly than it began with the coming of darkness1 but on a recent occasion ,vorhies observed that a kangaroo rat which did not appear until near morning remained above ground until quite light1 but not fully daylight4 ,on removal of the plug from the mouth of a kangaroo rat burrow1 one may sometimes see a fresh mass of earth and refuse shoved into the opening from within4 ,as often as not1 however1 even this unwelcome attention does not elicit any response by day1 the great majority of the burrow openings of this species1 as observed by the authors1 remaining permanently open4 ,the ordinary activities of the kangaroo rat in southern ,arizona can scarcely be said to show any true seasonal variation4 ,the animals are active all the year in this region1 there being neither hibernation nor estivation1 both perhaps being rendered unnecessary by the storage habit1 to be discussed in full later 7pp4 #ae-af71 and by the mildness of the winter climate4 ,on any particular night that the weather is rainy1 or the ground too wet and cold1 activity is confined to the interior of the burrow system1 and for this reason one has no opportunity to see a perfect imprint of the foot in freshly wet soil or in snow4 ,on two or three of the comparatively rare occasions on which there was a light fall of snow on the ,range ,reserve a search was made for tracks in the snow4 ,at these times1 however1 as on rainy nights1 the only signs of activity were the pushing or throwing out of fresh earth and food refuse from within the burrow4 ,this is so common a sight as to be complete evidence that the animals are active within their dens during stormy weather but do not venture outside4 ,trapping has again and again proved to be useless on rainy nights1 unless the rain is scant and a part of the night favorable1 in which case occasional individuals are taken4 ,these statements apply to the ,range ,reserve particularly2 the facts may be quite different where the animals experience more winter1 as at ,albuquerque1 ,n4 ,mex41 although in ,november1 #aiba1 ,vorhies noted no indications of lessened activity in that region4 ,,pugnacity ,,and ,,sociability4 ,so far as their reactions toward man are concerned1 kangaroo rats are gentle and make confiding and interesting pets2 this is especially the case with merriami4 ,this characteristic is the more surprising in view of the fact that they will fight each other so readily and so viciously1 and yet probably it is explained in part by their method of fighting4 ,they do not appear to use their teeth toward each other1 but fight by leaping in the air and striking with the powerful hind feet1 reminding one most forcibly of a pair of game cocks1 facing each other and guarding in the same manner4 ,sometimes they carry on a sparring match with their fore feet4 ,biting1 if done at all1 is only a secondary means of combat4 ,when taken in hand1 even for the first time1 they will use their teeth only in the event that they are wounded4 ,the jaws are not powerful1 and though the animals may lay hold of a bare finger1 with the apparent intention of biting1 usually they do not succeed in drawing blood4 ,as ,bailey says 7#aije1 #adh71 they are gentle and timid1 and1 like rabbits1 depend upon flight and their burrows for protection4 ,the well-traveled trails elsewhere described 7p4 #aj7 indicate a degree of sociability difficult to explain in connection with their pugnacity toward each other4 ,while three or four individuals may sometimes be trapped at a single mound1 more than two are seldom so caught1 and most often only one in one night4 ,trapping on successive nights at one mound often yields the larger number1 yet in some cases the number is explained by the fact that two or three nearly mature young are taken1 and the capture of several individuals at a single mound can not be taken to indicate that all are from the one den4 ,our investigations tend strongly to the conclusion that only one adult occupies a mound1 except during the period when the young are in the parental 7or maternal7 den4 ,in the gassing and excavating of #be or more mounds we have never found more than one animal in a den1 except in one instance1 and then the two present were obviously young animals4 ,,sense ,,developments4 ,without making special investigations through a study of behavior or other special methods1 one can speak in only general terms regarding what appear to be the special sense developments of kangaroo rats4 ,the eyes are large1 as is very often the case in nocturnal animals1 and when brought out into the bright light of day the rats perhaps do not see well4 ,yet1 if an animal leaves a den which is in process of excavation1 and follows one runway1 even in bright sunlight1 it makes excellent speed to the next opening1 often a distance of several yards4 ,whether this is accomplished chiefly by the aid of sight or in large measure by a maze-following ability1 such as experiments have shown some rodents to have1 can not be stated without precise experimentation4 ,marked ability to follow a maze would not be at all surprising in view of the labyrinthine character of the underground passages which make up the normal habitation4 ,when watching beside a mound by moonlight one is impressed with the fact that the rats possess either a very keen sense of hearing or of sight1 probably both4 ,the very slightest movement or noise on the part of the observer results1 with a timid individual1 in an instantaneous leap for safety1 a disappearance into the burrow so sudden as to be almost startling4 ,all attempts to obtain flashlight photographs at the mounds were failures1 the animal either having gotten completely out of the field before the light flashed following the pull of the trigger1 or leaving merely an indistinguishable blur on the plate as it went1 and this in spite of carefully hiding the trigger chain behind a screen4 ,a slight noise accompanying the trigger action gave the alarm in one case1 and in another the length of time of the flash was sufficient for the get-away4 ,the marvelous quickness of the animal clearly indicates a remarkably short reaction time4 ,occasionally a bold individual is found1 as in the case of one which came out repeatedly1 even after being flashed twice in the same night4 ,certain peculiar physical characteristics suggest a relationship to sense reactions4 ,on these1 however1 the authors are not prepared to do more than offer suggestions for future work4 ,the extremely large mastoids found in kangaroo rats suggest a connection in some way with special developments of the sense of hearing or of balance4 ,it may be noted that an intermediate condition between the kangaroo rats and the majority of rodents in respect to this character is to be found in the pocket mice 7,perognathus71 which belong to the same family4 ,herein lies a field for some interesting experimentation and discovery4 ,the small1 pointed nose might suggest a not overkeen sense of smell1 and there appears no reason to believe that this sense is particularly well developed4 ,however1 the turbinals are very complex4 ,the vibriss are long and sensitive1 and may indicate a special development of the sense of touch as an adaptation to nocturnal habits and to life in an underground labyrinth4 ,the long1 well-haired tail doubtless serves as an important tactile organ as well as a balance4 ,,movements ,,and ,,attitudes4 ,movements and attitudes are characteristic4 ,as a kangaroo rat emerges from the burrow a reason for the relatively large size of the opening is seen in the fact that1 kangaroolike1 the animal maintains a partially upright position4 ,its ordinary mode of progression is hopping along on the large hind legs1 or1 when in the open and going at speed1 leaping4 ,when moving slowly about over the mound1 as if searching for food1 it uses the fore legs in a kind of creeping movement4 ,it appears to be creeping when pocketing grain strewn about1 but close observation shows that the fore feet are then used for sweeping material into the pockets1 reminding one somewhat of a vacuum cleaner4 ,when it assumes a partially upright position the fore limbs are usually drawn up so closely that they can be seen only by looking upward from a somewhat lower level than that occupied by the animal4 ,the slower movements of searching or playing about the mound are occasionally interrupted by a sudden leap directly upward to a height of #a-a_/b to #b feet1 often with no apparent reason other than play4 ,this is1 however1 a fighting or guarding movement1 though indulged in for play4 ,the play instinct seems to be well developed1 and in evidence on any moonlight night when actual harvesting operations are not going on4 ,,storing ,,habits4 ,probably no instinct is of greater importance to the kangaroo rat than that of storing food supplies4 ,when a crop of desirable seeds is maturing the animal's activities appear to be concentrated on this work4 ,during ,september1 #aiai1 when a good crop of grass seed was ripening following the summer rains1 a kangaroo rat under observation made repeated round trips to the harvest field of grass heads4 ,each outward trip occupied from #a to #a-a_/b minutes1 while the unloading trip into the burrow took only #ae to #bj seconds4 ,one individual in a laboratory cage1 which had not yet been given a nest box1 busied itself in broad daylight in carrying its grain supply into the darkest corner of the cage4 ,when a nest box is supplied the individual will retreat into its dark shelter1 and will only come forth after darkness has fallen unless forcibly ejected1 but will store the food supplied4 ,in another case an animal escaped while being handled1 and sought refuge behind a built-in laboratory table1 where it could not be recovered without tearing out the table4 ,for four days and nights it had the run of the laboratory4 ,on the first night of its freedom it found and entered a burlap bag of grass seed that had been taken from a mound4 ,a trail of seed and chaff next morning showed that it had been busily engaged in making its new quarters comfortable with bedding and food4 ,after four nights of freedom it was captured alive in a trap1 and later it was found that it had moved from the corner behind the table to the space beneath a near-by drawer1 where it had stored about #b quarts of the grass seed and a handful of the oatmeal used for trap bait4 ,,breeding ,,habits4 ,observations on breeding habits have consisted mainly in taking records from the females trapped at all seasons of the year throughout the course of the investigation1 and from examinations made during poisoning operations1 and yet from this source the number of pregnant females taken or of young discovered is disappointingly small4 ,the records indicate a breeding period of considerable length1 extending from ,january to ,august1 inclusive4 ,it is possible that the length of the period may be increased by a second litter from the earliest breeding females in summer1 but the large percentage of nonpregnant or nonbreeding animals which occurs throughout the season would indicate a wide variation in the time of breeding of different individuals4 ,trapping in ,february and ,march for the purpose of securing greater numbers of female specimens1 begun with the idea that these months were most likely to be the breeding months1 has invariably yielded an unsatisfactory number of nonbreeding specimens and males4 ,unfortunately1 the numbers of females secured in some months were not sufficient to be significant if worked out in percentages of breeding and nonbreeding individuals1 and this1 coupled with the fact that the importance of recording carefully all nonbreeders was not at first recognized1 makes it impossible to tabulate such information reliably4 ,the total of females taken in ,april1 for example1 is only #c1 of which #a was breeding2 while in ,june1 during the course of poisoning operations1 #de females were examined1 of which #ba were breeding4 ,five breeding females were taken in ,january1 all during the last three days of the month4 ,one of these was a suckling female1 the young of which were secured alive and were probably at least a week old when taken4 ,this must have been exceptionally early for young1 since of a number of adult kangaroo rats taken during the first week of ,january none have been found to be breeding4 ,two records from ,vernon ,bailey are as follows3 ,may #ai-;,june #h1 #aijc1 young specimen in nest 7,santa ,rosa1 ,n4 ,mex472 ,june #ab1 #ahhi1 one female1 two embryos 7,oracle1 ,ariz474 ,the considerable proportion 7which we believe to be more than #ej per cent7 of nonbreeding females taken during all those months in which breeding has been found to occur may also indicate an extended period of breeding1 with a small percentage breeding at any one time4 ,this period also furnishes ample time for the rearing of two litters a year by some females1 but we have no evidence as to the occurrence of two litters4 ,young of the year1 practically grown1 are taken during and after the month of ,april4 ,the mammae are arranged in three pairs1 pectoral1 #a_/a2 inguinal1 #b_/b4 ,kangaroo rats are among those rodents in which the vagina becomes plugged with a rather solid material1 translucent1 and of the consistency of a stiff gelatine1 after copulation4 ,this must occur very soon after coitus1 since in those individuals taken in this condition no definite evidence of the beginning of development of embryos could be detected by examination4 ,the length of the gestation period of spectabilis is unknown4 ,the young are born naked1 a fact inferred by failure to find any fetus showing noticeable hair development1 and from the conditions observed in such young as have been seen4 ,a suckling female was taken by ,vorhies1 ,january #ca1 #aibj1 and her den immediately excavated in the hope of securing the young4 ,two juveniles were found in a special nest chamber 7see p4 #cj74 ,these were estimated to be perhaps two weeks old4 ,a serious effort was made to raise the little animals by feeding milk with a pipette and keeping them warm with a hot water bottle1 but they survived only #aj days1 without the eyes having opened4 ,the uneven temperature as well as the character of the food was probably responsible for their deaths4 ,on ,february #c they were measured and weighed1 with the following results3 ---------------------------------------- ----------- ,measurements 7in millimetres74 ,weight ------------------------------- 7in ,total ,tail ,hind grams74 length4 vertebrae4 foot4 ---------------------------------------- ------- ,no4 #a #ac4c #ij #ch #bd ,no4 #b #ab4f #ic #ch #bd ---------------------------------------- ----------- ,at this stage the young were partially clothed with a coat of fine velvety fur1 more especially on the bodies1 the tails being still nearly naked4 ,the body color was dark plumbeous1 just the color of the dark underfur of the adult1 or a shade darker1 while the characteristic white markings of the adult stood out sharply as pinkish-white areas against the dark background 7see ,pl4 ,,ix1 ,fig4 #b1 at p4 #cb74 ,the proportions were much as in the adult1 except that the tails were relatively much shorter and the feet relatively longer4 ,only one other record of young is at hand1 that by ,bailey1 who secured the young after capture of a suckling female at ,santa ,rosa1 ,n4 ,mex4 ,in this case the litter contained only one4 ,this was squeaking when found1 but was not large enough to crawl away4 ,its eyes and ears were closed1 and its soft1 naked skin was distinctly marked with the pattern of the adult1 the colors being as given for the other two4 ,this juvenile lived only a week4 ,young less than half grown were not trapped or noted in our poisoning operations outside the dens4 ,kangaroo rats1 if spectabilis be representative1 reproduce at a slow rate as compared with many other small rodents4 ,we have records of #fg females with embryos or scars showing the number produced1 and of the two litters of young described above4 ,of the #fi females thus recorded1 #ae1 or #ba4g per cent1 had but one offspring each2 #eb1 or #ge4c per cent1 but two each2 while only #b individuals1 or #b4i per cent1 had three4 ,three young is the maximum litter recorded4 ,this1 taken in connection with the protracted breeding season and lack of sure evidence of the production of two broods a year1 gives a surprisingly low rate of reproduction1 indicating relative freedom from inimical factors4 ,our breeding records for merriami are fewer than for spectabilis1 but are very similar in every way so far as they go1 both as to the time of year and number of young4 ,,food ,,and ,,storage4 ,dipodomys s4 spectabilis does not hibernate1 so must prepare for unfavorable seasons by extensive storage of food materials4 ,there are two seasons of the year1 in southeastern ,arizona at least1 when storage of food takes place1 namely1 in spring1 during ,april or ,may1 and in fall1 from ,september to ,november1 the latter being the more important4 ,for the periods between1 the animal must rely largely on stored materials4 ,not infrequently a season of severe drought precludes the possibility of any storage4 ,the summer and fall of #aiah was such a season on the ,range ,reserve 7,pl4 ,,ii1 ,fig4 #b74 ,if food stores are inadequate at such a time the kangaroo rats must perish in considerable numbers4 ,fisher found many deserted mounds in the vicinity of ,dos ,cabezos1 ,ariz41 in ,june1 #ahid1 which may be accounted for in this way4 ,in #aiba ,vorhies found all mounds within #d or #e miles of ,albuquerque1 ,n4 ,mex41 deserted by spectabilis1 resulting probably from overgrazing by sheep and goats during a succession of dry years4 ,in the arid ,southwest natural selection probably favors the animals with the largest food stores1 and it is not surprising that the storing habit has been developed to a remarkable degree4 ,some stored material is likely to be found at any time of year in any mound examined1 the largest quantity usually in fall and winter1 the smallest in ,july or ,august 7,table #a1 dens #a1 #b1 #ad1 and #bd74 ,amounts found by different observers vary from a few ounces to several quarts or pecks1 and stored materials taken from #bb mounds on the ,range ,reserve vary in weight from #e to #d1abg grams 7more than #i pounds74 ,this is exceeded by one lot from ,new ,mexico1 which totaled #e1gej grams 7#ab4fg pounds74 ,it is fairly evident that in seasons of scanty forage for stock the appropriation of such quantities of grass seeds and crowns and other grazing materials by numerous kangaroo rats may appreciably reduce the carrying capacity of the range4 ,studies of cheek-pouch contents and food stores taken from dens show that the natural food of spectabilis consists principally of various seeds and fruits1 particularly the seeds of certain grasses4 ,the study of burrow contents has been especially illuminating and valuable4 ,all of the stored material from #bb dens on the ,range ,reserve and from #b near ,albuquerque1 ,n4 ,mex41 has been saved and analyzed as to species as carefully as the conditions of storage would permit4 ,within the mound the food stored is usually more or less segregated by plant species1 though the stores of material of any one kind may be found in several places through the mound1 and often the material is mixed4 ,in the latter case the quantities of the various species can only be estimated1 but in the former the species may be kept separate by the use of several bags for collecting the seeds1 and a fairly accurate laboratory weighing can be made later4 ,very frequently1 the explanation of this separation of species lies in the different seasons of ripening1 but sometimes where two species are ripe at the same time near the mound1 one is worked upon for a time to the exclusion of the other4 ,the one kind is often packed in tightly against the other1 but with a very abrupt change in the character of the material4 ,a number of the more interesting and representative results of the weighing and analyses of burrow contents are presented herewith in tabular form4 ,the data for each den1 or lot1 shows in grams the quantity of stored material removed and the best estimate it was possible to make of the percentages or weights of the various species4 ,when the weight was less than #e grams1 the mere trace of the species frequently is indicated in the following tables by the abbreviation ,tr4 ,,table #a4--;,analyses of plants stored by ,dipodomys spectabilis spectabilis ,merriam1 obtained from examination of representative dens 7all except ,den #bd from ,u4 ,s4 ,range ,reserve1 near the ,santa ,rita ,mountains1 ,ariz474 ,,den #a4 ,february #g1 #aiah4 ,burrow typical1 located on bank of wash in partially denuded grass-land1 ,bouteloua rothrockii and weed type2 soil sandy2 burrow photographed in section 7,pl4 ,,vii1 ,fig4 #a74 ,species stored4 ,grams4 ,bouteloua rothrockii #b1bje ,bouteloua aristidoides 7,b4 eriopoda and ,b4 rothrockii1 ,tr47 #a1dde ,plantago ignota #ddb ,eriogonum polycladon #ce ----- ,total #d1abg ,four species of plants represented in burrow contents 7,pl4 ,,vii1 ,fig4 #b74 ,maximum quantity for single burrow in series of #bb from ,range ,reserve4 ,,den #b4 ,march #i1 #aiah4 ,surroundings overgrazed and partially restored by complete protection4 ,red soil1 with much coarse rough gravel and stone4 ,species stored4 ,grams4 ,bouteloua rothrockii 7nearly pure7 #a1dfj ,bouteloua rothrockii 7mixed with ,aristida spp47 #ide ,boerhaavia wrightii #ffj ,bouteloua rothrockii ,bouteloua aristidoides #ebe ,aristida divaricata ,aristida bromoides ,kallstroemia laetevirens ,tr4 ,heterotheca subaxillaris ,tr4 ,plantago ignota #ae ,fleshy fungi #aj ----- ,total #c1fae ,eight species of plants represented by seeds4 ,one species of fleshy fungus in addition4 ,,den #d4 ,september #bj1 #aiah4 ,in ,calliandra type4 ,stony or gravelly soil1 red1 nearly denuded of grass4 ,species stored4 ,grams4 ,prosopis velutina #aij ,mollugo verticillata 7pure7 #ij ,anisolotus trispermus 7mixed1 but mostly of this genus7 #ej ,solanum elaeagnifolium 7#ab fruits7 #b ,per cent4 ,mollugo verticillata 7inseparable7 #ej ,bouteloua rothrockii #a ,bouteloua aristidoides #aj ,lepidium lasiocarpum ,tr4 ,polygala puberula ,tr4 ,ayenia microphylla #b ,portulaca suffrutescens #a #djj ,aplopappus gracilis ,tr4 ,alternanthera repens #a ,tridens pulchella #a ,plantago ignota #cc ,panicum hallii ,tr4 ,fleshy fungi 7puffballs7 #b --- ,total #gcd ,fifteen species represented in addition to the fleshy fungi4 ,no perceptible grass growth from the summer rains here1 therefore dependent on a wide variety of scattering plants4 ,,den #f4 ,october #ag1 #aiah4 ,mixed type1 partially denuded1 no growth from summer rains4 ,sandy soil4 ,species stored4 ,grams4 ,bouteloua rothrockii 7crowns7 7heads #a to #b per cent7 #a1dce ,bouteloua rothrockii 7heads and crowns1 about #ej per cent of each7 #cbe ,bouteloua rothrockii 7with small percentage of crowns7 #cae ,boerhaavia wrightii 7with a few grass crowns7 #aej ,prosopis velutina #ij ,solanum elaeagnifolium 7#c fruits7 ,tr4 ----- ,total #b1cae ,four species represented4 ,count of #ajj grams of stored ,bouteloua crowns gives #a1gjj1 or #ag crowns per gram4 ,at this rate there were at least #bg1jjj crowns stored in this burrow4 ,if a density of #bej plants to the square yard be assumed 7a high estimate7 these crowns represent the total ,b4 rothrockii on #ajd square yards of range surface4 ,further examination of the vicinity of this den showed that the surrounding area was not completely cleared1 but was devoid of ,b4 rothrockii1 while still having ,b4 eriopoda with crowns undisturbed4 ,,den #aa4 ,april #i1 #aiai4 ,in partially denuded land where good spring growth of ,eschscholtzia was in bloom at time of excavation4 ,stomach of spectabilis killed in this burrow contained a mass of fresh but finely comminuted green material1 probably poppy leaves1 strongly colored with yellow from blossoms4 ,no summer growth here in #aiah4 ,species stored4 ,grams4 ,bouteloua rothrockii 7crowns7 7miscellaneous chaff1 etc47 #ajg ,eschscholtzia mexicana 7buds and flowers7 ,anisolotus trispermus 7leaves and pods7 ,gaertneria tenuifolia 7leaves7 #aj ,lupinus sparsiflorus 7flowers7 ,solanum elaeagnifolium 7#b fruits7 ,tr4 --- ,total #aag ,six species represented1 some only by leaves or flowers and not by seeds4 ,such storage is never in large quantity4 ,the fresh storage material was weighed after becoming air dry4 ,this illustrates a late spring condition1 storage running low4 ,,den #ad4 ,august #h1 #aiai4 ,excellent summer growth all over range4 ,this burrow in mixed growth1 grasses and weeds4 ,species stored4 ,grams4 ,miscellaneous portions of green plants of mixed species1 no seeds #e ,representing minimum for any one of the #bb burrows studied4 ,active storage does not begin until ,september4 ,,den #af4 ,october #ag1 #aiai4 ,in good grass1 but mound overrun by a large ,apodanthera vine4 ,species stored4 ,per cent4 ,grams4 ,aristida divaricata #ij to #ie ,chamaecrista leptadenia #aj to #e #eh ,bouteloua rothrockii ,tr4 ,prosopis velutina #bjj ,apodanthera undulata #ee --- ,total #cac ,five species represented4 ,two species1 ,apodanthera1 and ,chamaecrista leptadenia1 new to storage records4 ,several whole fruits of ,apodanthera1 about #b inches in diameter1 stored in addition to seeds alone2 seeds of this form not previously noted in burrows1 but very abundant in this one1 indicating importance of the factor of accessibility in storage4 ,,den #ai4 ,october #ca1 ,november #a1 #aiai4 ,in good grass4 ,entire burrow system mapped 7,fig4 #b1 p4 #bi74 ,species stored4 ,per cent4 ,grams4 ,aristida spp4 7probably mostly divaricata7 #ih ,eriogonum sp ,tr4 ,bouteloua rothrockii #a #a1hac ,bouteloua aristidoides #a ,panicum sp ,tr4 ,prosopis velutina #a1bac ----- ,total #c1jbf ,five species represented1 in addition to those of ,aristida4 ,largest storage of ,prosopis found4 ,mound was near a good-sized mesquite tree4 ,no storage in subsidiary burrows4 ,,den #ba4 ,january #ca1 #aibj4 ,male trapped here night of ,january #bi1 and suckling female trapped at same place and same opening of mound1 night of ,january #cj4 ,burrow excavated to secure young1 which were found in special nest chamber4 ,species stored4 ,grams4 ,aristida spp4 7intimate mixture of undetermined species7 #a1aae ,eschscholtzia mexicana 7from spring of #aiai7 #dh ,opuntia 7prickly pear1 seeds only1 no fruits7 #aj ----- ,total #a1agc ,three species represented4 ,prickly pear hitherto found as fruits only4 ,,den #bb4 ,january #a1 #aiba4 ,rather good grass growth here in summer of #aibj4 ,burrow typical1 sandy soil4 ,two skulls of former residents unearthed4 ,species stored4 ,grams4 ,aplopappus gracilis 7some ,b4 rothrockii7 #a1jcj ,astragalus nuttallianus #fcj ,bouteloua rothrockii 7some ,a4 gracilis7 #ecj ,sida diffusa #cj ,solanum elaeagnifolium 7#bhb fruits7 #ec ,loeflingia pusilla ,tr4 ,bouteloua aristidoides ,tr4 ,plantago ignota ,tr4 ,lupinus sparsiflorus ,tr4 ,old storage 7mostly ,bouteloua aristidoides with traces of ,b4 rothrockii and ,aristida divaricata7 #fj ----- ,total #b1ccc ,eleven species represented4 ,first instance of quantity storage of ,aplopappus gracilis4 ,first occurrence of ,loeflingia pusilla and ,astragalus nuttallianus4 ,,den #bd4 ,november #h1 #aiba4 ,on mesa northeast of ,albuquerque1 ,n4 ,mex41 near base of ,sandia ,mountains4 ,fair grass growth here during preceding summer4 ,species stored4 ,grams4 ,sporobolus cryptandrus strictus #e1dee ,salsola pestifer #bie ----- ,total #e1gej ,two species represented4 ,the heads of ,sporobolus cryptandrus strictus are retained to a great extent within the leaf sheaths4 ,this necessitates the cutting of the stems into suitable lengths for carrying1 and the stored material appears to be merely cut sections of the stems4 ,close examination1 however1 discloses the heads within1 and shows that as in other instances seed storage is the end sought4 ,these pieces are packed beautifully parallel like so many matches1 and vary from a minimum length of #bj to a maximum of #cg millimeters1 averaging about #cj4 ,count of #b grams of the above ,sporobolus material shows that there are #abe separate cut sections per gram1 or a total of approximately #fhj1jjj pieces in this one lot of storage1 indicating a remarkable activity on the part of the individual rat 7,pl4 ,,viii1 ,fig4 #a74 ,illustration3 ,,plate ,,vii4 ,,fig4 #a4--;,,den ,,excavated ,,on ,,range ,,reserve4 ,vertical section through ,den ,no4 #a1 of ,table #a 7p4 #bj71 showing the complex system of burrows1 some of them plugged with closely packed storage 7outlined in white71 the depth of the den1 and the widened chambers centrally located4 ,illustration3 ,,plate ,,vii4 ,,fig4 #b4--;,,content ,,of ,,excavated ,,den4 ,storage content of ,den ,no4 #a 7,fig4 #a1 above71 showing the separate species of plants listed in ,table #a4 ,the rod is #a meter long4 ,the large pile on the left is composed of seed-laden heads of crowfoot grama 7,bouteloua rothrockii71 the large pile on the right consists of heads of six-weeks grama 7,bouteloua aristidoides71 the pile of heads in the center is desert plantain 7,plantago ignota71 and the smallest heap is composed of buckwheat-bush seeds 7,eriogonum polycladon74 ,the number of lots of storage 7#bd7 studied in detail1 extending as it does over a period of three years with seasons of varying growth conditions1 is not sufficient to permit the construction of a curve showing increase and decrease in quantity of stored material with growing seasons and intervals between2 but the results indicate a very decided increase during the autumn storing season1 and continuing large well into the winter1 since some outside material can still be obtained until midwinter4 ,from about ,february to ,april a decrease may be noted1 followed1 if the spring growth of annuals be good1 by a slight increase2 and we can very nearly predict the general character of the increases and decreases by the precipitation and consequent growth conditions4 ,,table #b4--,quantity of storage per den correlated with time of year and growth conditions of preceding season 7chiefly from ,united ,states ,range ,reserve near the ,santa ,rita ,mountains1 ,ariz474 ---------------------------------------- ----- ,den ,no4 ,date4 ,quantity4 ,preceding season4 ---------------------------------------- ----- #aiah4 ,grams4 #a ,feb4 #g #d1abg ,good4 #b ,mar4 #i #c1fae ,do4 #c ,july #be #dja ,poor4 #d ,sept4 #bj #gcd ,do4 #e ,sept4 #ba #b1ebj ,do4 #f ,oct4 #ag #b1cae ,do4 #g ,dec4 #bj #a1bdg ,do4 #aiai4 #h ,feb4 #g #a1fjj ,do4 #i ,mar4 #ac #cgj ,do4 #aj ,apr4 #g #ahj ,do4#c #aa ,apr4 #i #aag ,good4#c #ab ,may #g #bih ,do4#c #ac ,may #aa #a1eij ,do4 #ad ,aug4 #h #e ,good4 #ae ,sept4 #d #aea ,do4 #af ,oct4 #ag #cac ,do4 #ag ,oct4 #ah #ehc ,do4 #ah ,oct4 #be #c1daj ,do4 #ai ,nov4 #a #c1jbf ,do4 #bj ,dec4 #ac #b1haf ,do4 #aibj4 #ba ,jan4 #ca #a1agc ,do4 #aiba4 #bb ,jan4 #a #b1ccc ,fair4 #bcd ,nov4 #g #a1fhe ,good4 #bdd ,nov4 #h #e1gej ,do4 ---------------------------------------- ----- ,footnote #c3 ,changing from poor summer season of #aiah to excellent spring growth of #aiai4 ,footnote #d3 ,from near the ,sandia ,mountains1 ,n4 ,mex42 others from ,united ,states ,range ,reserve1 near the ,santa ,rita ,mountains1 ,ariz4 ,in presenting ,table #b1 showing quantity of storage per burrow correlated with the time of year and the character of the preceding growing season1 the fact may be emphasized that the growing seasons in southern ,arizona are two in number--early spring and midsummer4 ,the spring season is the less important1 the plants consisting chiefly of a variety of small annuals1 while the important range grasses make their chief growth and head out almost exclusively in the ,july-,august rainy season4 ,it may be noted also that the actual increases in storage appear somewhat after the growth period proper1 since storing does not get well under way until the seed crop is mature4 ,the banner-tailed kangaroo rat shows a marked adaptability to different foods available in the neighborhood of its burrows4 ,it must1 perforce1 adapt itself and its storage program to the food that it can get1 and this varies enormously with the climatic conditions of successive seasons4 ,the large numbers present in suitable localities clearly indicate that the animal is successful in meeting the changing and sometimes extremely adverse conditions of its environment4 ,illustration3 ,,plate ,,viii4 ,,fig4 #a4--;,,content ,,of ,,den ,,excavated ,,in ,,new ,,mexico4 ,storage content of ,den ,no4 #bd1 of ,table #a1 from ,sandia ,mountains1 ,n4 ,mex4 ,this is the largest lot of storage taken in the course of the investigations4 ,the larger pile consists wholly of a valuable grass1 ,sporobolus cryptandrus strictus3 the smaller of ,russian thistle 7,salsola pestifer47 ,illustration3 ,,plate ,,viii4 ,,fig4 #b4--;,,growth ,,following ,,elimination ,,of ,,kangaroo ,,rats4 ,the same mound as shown in ,plate ,,iii1 ,figure #a1 after three years of protection1 the rodents having been killed out4 ,nearly as good grass recovery following poisoning operations occurred in the single excellent season of #aiba4 ,at times1 more especially in the seasons of active growth1 some of the green and succulent portions of plants are eaten4 ,this was very noticeable in the spring of #aiai1 when a most luxuriant growth of ,mexican poppy 7,eschscholtzia mexicana7 occurred4 ,stomachs at this time were filled with the yellow and green mixture undoubtedly produced by the grinding up of the buds and flowers of this plant4 ,small caches of about a tablespoonful of these buds were also found in the burrows at this time4 ,occasionally in spring one may find a few green leaves of various plants1 ,gaertneria very commonly1 tucked away in small pockets along the underground tunnels1 indicating that such materials are used to some extent4 ,as has been shown in detail1 however 7,table #a71 the chief storage1 and undoubtedly the chief food1 consists of air-dry seeds4 ,the character of the storage1 the absence of rain for months at a time in some years1 and the consequent failure of green succulents show that without doubt spectabilis possesses remarkable power1 as to its water requirements1 of existing largely if not wholly upon the water derived from air-dry starchy foods1 i4e41 metabolic water serves it in lieu of drink 7,nelson1 #aiah1 #djj71 this being formed in considerable quantities by oxidation of carbohydrates and fats 7,babcock1 #aiab1 #aei1 #agj74 ,during the long dry periods characteristic of southern ,arizona1 no evidence that the animal seeks a supply of succulent food1 as cactus1 is found2 and if it may go for two1 three1 or six months without water or succulent food1 it is reasonable to suppose that it may do so indefinitely4 ,in the laboratory spectabilis ordinarily does not drink1 but rather shows a dislike for getting its nose wet4 ,during the periods of drought the attacks upon the cactuses by other rodents of the same region1 as ,lepus1 ,sylvilagus1 ,neotoma1 and ,ammospermophilus1 become increasingly evident4 ,the list of plant species thus far found represented in the storage materials of spectabilis on the ,range ,reserve is shown in ,table #c4 ,,table #c4--,list of all plant species found in #bb dens of ,dipodomys spectabilis on the ,united ,states ,range ,reserve1 near the ,santa ,rita ,mountains1 ,ariz41 with approximate total weights4 ,,grasses4 ,grams4 ,aristida bromoides 7six-weeks needlegrass7 #ecf ,aristida divaricata 7,humboldt needlegrass7 #i1dab ,aristida scabra 7rough needlegrass7 #cdd ,bouteloua aristidoides 7six-weeks grama7 #c1jic ,bouteloua radicosa 7grama7 #a1bfi ,bouteloua eriopoda 7black grama7 ,tr4 ,bouteloua rothrockii 7seeds1 #h1die2 crowns1 #c1eag grams7 7crowfoot grama7 #ab1jab ,festuca octoflora 7fescue grass7 #gj ,panicum arizonicum 7,arizona panic-grass7 #aa ,panicum hallii 7,hall panic-grass7 ,tr4 ,pappaphorum wrightii ,tr4 ,tridens pulchella ,tr4 ,valota saccharata ,tr4 ,,other ,,plants4 ,alternanthera repens ,tr4 ,anisolotus trispermus 7bird's-foot trefoil7 #ahf ,aplopappus gracilis #a1jcj ,apodanthera undulata 7melon loco7 #ee ,astragalus nuttallianus 7milk vetch7 #fcj ,ayenia microphylla ,tr4 ,boerhaavia wrightii #hhe ,chamaecrista leptadenia 7partridge pea7 #e ,echinocactus wislizeni 7visnaga7 #e ,eriogonum polycladon #ce ,eschscholtzia mexicana 7,mexican poppy7 #bej ,gaertneria tenuifolia 7franseria7 ,tr4 ,collomia gracilis 7false gilia7 ,tr4 ,heterotheca subaxillaris ,tr4 ,kallstroemia laetevirens ,tr4 ,lupinus sparsiflorus 7lupine7 ,tr4 ,martynia altheaefolia 7small devil's-horns7 #ab ,mollugo verticillata 7carpetweed7 #cbd ,oenothera primiverus 7evening primrose7 #ae ,opuntia discata 7prickly pear7 #ae ,loeflingia pusilla ,tr4 ,lepidium lasiocarpum 7peppergrass7 ,tr4 ,plantago ignota 7plantain7 #hah ,polygala puberula 7milkwort7 ,tr4 ,portulaca suffrutescens 7purslane7 ,tr4 ,prosopis velutina 7mesquite7 #a1egj ,sida diffusa 7spreading sida7 #cj ,solanum elaeagnifolium 7#gdb fruits7 7trompillo1 prickly solanum7 #aef ,puffballs and fleshy fungi 7undetermined7 #ab ,total species1 exclusive of fungi1 #da4 ,it will be seen from ,table #c that while a large number of species of plants are represented in the totals from so many dens1 a majority of them are of very minor importance1 and that the seeds of grasses are the principal storage and probably therefore the principal food material4 ,six of the most important species of grasses 7disregarding species furnishing less than #e grams7 comprise #he4f per cent of the total weight of storage from #bb dens4 ,crowfoot grama 7,bouteloua rothrockii7 stands first in quantity in the total1 forming #ci4d per cent of all stored material1 #df per cent of the six important grasses1 and #de per cent of all grasses4 ,the largest amount of storage of any one species of grass in any one den on the ,range ,reserve also is of this species1 #b1bje grams#e 7,table #a1 den #a1 p4 #bj1 and ,pl4 ,,vii1 ,fig4 #b74 ,this is exceeded by a dropseed grass1 ,sporobolus cryptandrus strictus1 which amounted to #e1dee grams in a lot from ,albuquerque1 ,n4 ,mex4 7,table #a1 den #bd1 and ,pl4 ,,viii1 ,fig4 #a74 ,footnote #e3 ,this amount of dry grama grass seed 7heads7 amounts to approximately a bushel4 ,of the species other than grasses found stored in these dens1 mesquite beans 7,prosopis velutina7 are most important both by weight and number of dens containing them4 ,the total for the #bb ,range ,reserve dens is #a1egj grams1 or #ce4i per cent of the seeds other than grasses1 but only #e4a per cent of the total storage4 ,in bulk mesquite beans do not loom up large1 as they are probably the heaviest material stored4 ,sections of pods which must have been dragged into the burrows are found1 some of them certainly being much too long for carriage in the pouches4 ,the species of plant other than grass found in the largest quantity in any one den1 however1 was ,aplopappus gracilis1 not recorded in quantity from any den until the excavation of the twenty-second1 and then found in a very large bulk of soft1 fluffy material1 with most of the seeds separated from the heads1 and weighing #a1jcj grams 7,table #a1 den #bb74 ,any of the food materials above listed are likely to be found in the cheek pouches1 while in addition such extraneous matter as stones and feces have also been found4 ,all species of plants stored are accessible in the immediate vicinity of the mound1 and when any particular plant is found seeding in abundance in the vicinity of the den it is likely to be represented in the storage4 ,usually the animals can be readily trapped with almost any kind of grain bait1 as oats1 rolled oats1 rolled barley1 and wheat2 and nut meats also are attractive1 though we have no record of the storing of any true nut in the dens1 such not being available in the range of the animal on the ,range ,reserve4 ,the following plants not represented in the list stored by the kangaroo rat on the ,range ,reserve have been found in the cheek pouches or mounds of spectabilis in other localities3 ,amaranthus palmeri1 ,sesuvium portulacastrum1 and ,atriplex wrightii 7alluvial soil of ,santa ,cruz ,valley1 ,continental1 ,ariz41 ,bailey74 ,cut leaves and stems of a small sagebrush 7,franklin ,mountains1 ,tex41 ,gaut74 ,gutierrezia heads 7,san ,juan ,valley1 ,n4 ,mex41 ,birdseye74 ,verbesina enceliodes1 ,portulaca oleracea1 ,bouteloua gracilis1 and ,munroa squarrosa 7,rio ,alamosa1 ,n4 ,mex41 ,goldman74 ,tops of buds of ,artemisia filifolia 7,mesa ,jumanes1 ,n4 ,mex41 ,gaut74 ,tumbleweed 7,amaranthus graecizans71 ,russian thistle 7,salsola pestifer71 ,munroa squarrosa1 and ,sporobolus cryptandrus strictus 7,sandia ,mountains1 ,albuquerque1 ,n4 ,mex41 ,vorhies74 ,,burrow ,,systems1 ,,or ,,dens4 ,the burrow system1 or den1 in which spectabilis stores its caches of food materials1 has its nest1 and remains throughout the hours of daylight is a complicated labyrinth of tunnels4 ,ejection of refuse and soil from this retreat builds up the mound frequently referred to4 ,these mounds are1 as ,bailey says1 characteristic of the species1 and are as unmistakable as muskrat houses or beaver dams1 and as carefully planned and built for as definite a purpose--home and shelter4 ,they are1 furthermore1 the most notable of all kangaroo rat dwelling places 7,nelson1 #aiah1 #djj74 ,they range in height from #f inches to approximately #d feet and from #e to #ae feet in diameter4 ,the mound is built up not only through the cleaning out of chaff and other food refuse1 but through extension and modification of the tunnels2 old tunnels1 entrances1 and caches of musty food material are from time to time closed up and others excavated1 repair and rebuilding being especially necessary after the collapse of portions of the den as a result of heavy rains or trampling by cattle4 ,ejected material is most commonly simply thrown out fan-wise from the openings1 without much apparent effort to add to the height of the mound4 ,there are usually from #f to #ab entrance holes in each mound opening into the subterranean burrow system1 each hole from #d to #e-a_/b inches in diameter4 ,these holes are nearly all situated a little above the surface of the surrounding soil1 and as ,price has suggested 7in ,allen1 #ahie1 #bac71 this is doubtless a wise provision against flooding1 as torrential rains sometimes occur in the kangaroo rat country4 ,both ,bailey and ,nelson state that as a rule several of the holes are closed with sand or miscellaneous earth and old storage material during the daytime1 but our observations on the ,range ,reserve are that such closing is only occasional4 ,many occupied dens have not a single opening closed4 ,further1 night observations disclose that the inhabitant of the mound will appear from some one of the two or three most-used openings when night falls1 and not necessarily from one which has been closed by day4 ,recently an opening closed one day was observed in use during the night1 but was left open all the next day4 ,in attempting to determine whether there exist similarities of plan or system in the dens1 it was considered advisable to map them with some degree of accuracy4 ,this we were enabled to do by laying off a square about a given mound1 #b-a_/b or #c meters each way1 and subdividing it into a series of small squares of half a meter on each side by drawing cross-lines on the surface of the ground over the top of the mound4 ,one person then did the digging and exploring of the tunnels1 as to direction and depth1 while the other noted the results on coordinate paper 7,figs4 #b and #c72 the proper excavation and mapping of one of these workings occupied from four to eight hours for the two4 ,illustration3 ,,fig4 #b4--;,diagram of a typical den of ,dipodomys spectabilis spectabilis4 ,double shading indicates where one portion of tunnel lies above another and solid black a three-story arrangement2 ,a1 ,b1 ,c1 etc41 active openings to surface2 figures without arrows1 depths in centimeters to tunnel roofs2 figures with arrows1 tunnel widths in centimeters2 ,n4 nest chamber2 ,s1 storage2 ,,os1 old storage2 ,y1 probably an old nest chamber2 ,z1 old1 unused1 or partially plugged openings4 ,while there is greater complexity in the larger1 and probably older1 mounds than in the smaller1 all are extremely complicated and can only be described as labyrinthine in character4 ,the tunnels wind about through the mound1 rising and falling in vertical depth1 intercommunicating frequently1 but with occasional cul-de-sacs1 and in places expanding into chambers1 of which there may be three or four large ones4 ,the stored materials are found in some1 but not necessarily all1 of these chambers1 and may also occupy considerable lengths of ordinary tunnel1 especially when the quantity present is large4 ,small evaginations of the tunnels frequently contain lesser caches1 and it is in such pockets that bits of fresh material are placed during a growing season1 or that grain supplied the previous night for bait is usually found4 ,the main masses of storage are most often found centrally located at depths of from #ae to #eg centimeters1 although at times one may find a cache near the periphery of the system and as near the surface as #b or #c centimeters4 ,in the latter case the materials are subject to wetting from rains1 and consequent spoilage4 ,the major portion of the whole tunnel system is within about #ej centimeters of the surface of the mound1 but usually some one branch tunnel goes to somewhat greater depth1 and this is likely to be the one containing the nest2 this is also likely to extend toward or beyond the periphery of the main system1 and always ends blindly4 ,such a one1 from which two young were taken on ,january #ca1 #aibj1 was at a depth of about #fe centimeters1 and about #a-a_/b meters beyond the periphery of the mound itself4 ,the individual tunnels average about #h centimeters in height1 and about #aa centimeters in width1 though the variation1 especially in width1 is considerable4 ,the expansions mentioned as being the chief places of storage are from #ae to #be centimeters in diameter1 and may or may not involve a considerable increase in height4 ,they are frequently located at junction points of two or more branches of the tunnel system4 ,the nest cavity is a chamber of approximately spherical shape and from #ag to #bc centimeters in diameter4 ,chambers of this character were observed and noted as old storage in a number of cases4 ,they were sometimes cut off from the rest of the habitation1 and at first were supposed to contain abandoned musty storage4 ,as experience in excavating and interpreting results has been gained we have concluded that these chambers in fact represent abandoned nests4 ,illustration3 ,,fig4 #c4--;,diagram of the system of surface runways and subsidiary dens of ,dipodomys spectabilis spectabilis4 ,the underground tunnels of the main den were too complicated to illustrate on this scale1 being very similar to those of ,figure #b4 ,the underground tunnels of the subsidiaries are shown in solid black4 ,some runways fade out in the grass in a manner that can not be indicated in a line drawing4 ,bailey gives the dimensions of nest chambers observed in ,new ,mexico as about #f by #h inches to #h by #aj inches4 ,the nest is composed of finer1 softer1 and more chaffy material than the regular storage4 ,the chaff refuse from the food probably contributes largely to it1 though some leaves of grasses not stored for food may also be found1 and a nest1 especially the one in use1 may be distinguished1 if excavating is carefully done1 by the distinct cavity about the size of a fist in its interior 7,pl4 ,,ix1 ,fig4 #a74 ,one may sometimes find this cavity distinctly warm from the recent presence of the inhabitant4 ,the walls or partitions between the chambers and tunnels are in places surprisingly thin1 and it is no wonder that one is almost certain to break through in stepping on a mound1 since the whole is a honeycomblike structure of from two to four stories in vertical plan1 as shown by the transect of a mound in ,plate ,,vii1 ,figure #a4 ,as ,bailey writes1 these partition walls are a mixture of earth and old food and nest material discarded years ago1 resembling the adobe walls of the ,mexican houses built of chopped earth and straw4 ,this is the result of the continual ejection of refuse and earth as before mentioned1 combined with the caving action of rains and disturbances from larger animals4 ,apparently there are no special pockets for deposit of feces in ,dipodomys burrows2 such matter may be found throughout the den1 and is more or less mixed with the food refuse which carpets practically the entire tunnel system4 ,the nest and food stores are1 however1 clean and neat1 the droppings being dry and1 though present on the floor of a storage chamber1 not actually mingled with the food4 ,evidently the animal does not clean up the floor litter before storing food material4 ,the entire system for any one den seems to consist not only of the burrows within the mound itself1 as described1 but of those small outlying ones which we have referred to as subsidiary burrows4 ,these are two to four in number1 and are connected with the main mound by the runways already mentioned4 ,they often seem to be way stations on the runways connecting main mounds1 and there is seldom any mound of earth whatever in connection with them4 ,one entire den system1 the home mound and three subsidiaries1 was mapped after being excavated 7,fig4 #c71 all having been carefully gassed with carbon bisulphide4 ,the subsidiaries were simple and contained no storage4 ,two of them were shallow1 while in the third a depth of #dh centimeters was reached4 ,they appear to be merely places of refuge1 though the well-worn trails connecting them with the main mound indicate regular use4 ,these runways are conspicuous on the ,range ,reserve1 and are apparently characteristic of mounds throughout the range of the animal4 ,dwellers in different mounds must have rather extensive social contacts1 notwithstanding the enmity of individuals toward each other in captivity4 ,the main mound1 in this instance very complicated1 was in one place three stories high1 and we have found as many as four utilized stories2 but as a rule there are two or three only4 ,since collapses are rather frequent during rainy seasons1 aside from the trampling previously referred to1 the kangaroo rats1 where abundant1 as on the ,range ,reserve1 may well be a factor in increasing soil porosity and fertility2 for in the course of time they probably have succeeded in plowing and cultivating the whole surface layer of the soil4 ,they may thus be a factor in ecologic succession1 tending to improve the character of the soil and adapt it to another stage4 ,doubtless their own workings afford the only shelter the animals know4 ,in the course of our digging in one mound1 the occupant1 an adult male1 did not forsake the den until the excavation was three-fourths completed2 and even then it did not leave by a burrow leading away from our operations1 but came toward us1 escaped the active efforts of four individuals bent on its capture1 and ran speedily along a used runway toward another burrow several meters distant4 ,a sack had been stuffed in the mouth of this1 however1 and1 baffled1 the rat then returned to the original burrow and was captured4 ,observations on other rats thus driven from the home mound indicate that they are very familiar with the runways of the vicinity of the mound and the various subsidiary burrows1 and it is a question whether they need to see clearly to follow these runs4 ,apparently they never attempt to escape by forsaking their well-traveled runways4 ,tests of the maze-running ability of these animals by animal-behavior experts would be of extraordinary interest1 in view of the character of the homes which they always inhabit and the network of runs on the outside4 ,illustration3 ,,plate ,,ix4 ,,fig4 #a4--,,kangaroo ,,rat ,,nest ,,and ,,young4 ,nest and the two young1 the ordinary number in the litter1 of ,dipodomys s4 spectabilis1 taken from den on ,january #ca1 #aibj4 ,illustration3 ,,plate ,,ix4 ,,fig4 #b4--,,young ,,of ,,the ,,kangaroo ,,rat4 ,the same young as shown in ,figure #a1 above4 ,they were probably about two weeks old1 the pelage being short but with the white markings of the adult2 the tails are relatively short and with scarcely any hair4 ,,commensals ,,and ,,enemies4 ,,commensals4 ,it is doubtful whether any animals live in a truly commensal relationship with spectabilis1 but of not unfriendly associates there are a great number4 ,it is the experience of ,bailey1 corroborated by observations of ,vorhies on living animals1 that these kangaroo rats are active in defending their caches of food1 and will even fight individuals of the same species savagely and to the death4 ,one moonlight night a strange individual was liberated on a mound4 ,it deliberately entered one of the openings1 but after about two minutes' time made an exceedingly rapid exit1 running rapidly out of sight as if pursued1 though the owner of the home did not appear outside of the burrow4 ,there can be little doubt that the stranger was precipitately ejected by the owner4 ,we suspect1 though this is a point difficult to prove satisfactorily1 that merriami does not always store food supplies for itself1 but visits the burrows of spectabilis regularly to pilfer the seed stored therein4 ,the observed facts thus far recorded which suggest this are that in no merriami burrow examined has a store of food been found1 and also that in trapping for spectabilis on its own characteristic mounds one catches a large percentage of merriami4 ,on two separate occasions ,vorhies has observed the smaller species running over the mounds of the larger1 actually carrying away the grain which had been placed to entice the larger when it might appear4 7,in these cases the larger species did not put in an appearance until near morning47 ,furthermore1 the dens of merriami are often connected by distinct runways with those of spectabilis1 indicating much traveling or visiting4 ,that this is probably not friendly visiting is suggested by the certainty with which an individual of the larger species will strike and kill one of the smaller when they are placed together in the same inclosure4 ,the word thief expresses this suspected relationship better than would the term parasite4 ,it is not to be expected that such obvious shelter retreats as the mounds of spectabilis should fail to attract the attention of other animals4 ,we have found a small gecko 7,coleonyx variegatus71 scorpions of two or three undetermined species1 and certain insects 7of the ,order ,orthoptera7 to be very common inhabitants of the dens4 ,with the exception of the parasitic insects the most common are wingless locustids 7,ceuthophilus spp47 and the peculiar wingless females of a species of cockroach 7,arenivaga erratica74 ,these two are seldom absent when a burrow is excavated1 the female cockroaches being abundant1 although the winged males have never been taken in the burrows4 ,cary's observations at ,monahans1 ,tex41 and those of others at numerous localities1 combined with our own1 show that at various times the dens furnish protection and shelter for various species of cottontail rabbits 7,sylvilagus71 ground squirrels 7,citellus and ,ammospermophilus71 wood rats 7,neotoma71 grasshopper mice 7,onychomys71 rattlesnakes 7,crotalus71 and most of the common lizards4 ,of these the ground squirrels ,citellus tereticaudus and ,ammospermophilus harrisii are most often noted on the ,range ,reserve using the dens as a retreat1 the ,ammospermophilus seldom being observed to enter any other kind of burrow4 ,it should be added that the total observations include dens which have been deserted by their rightful owners4 ,,natural ,,checks4 ,the enemies of the kangaroo rat are not determined in detail1 or as to relative importance1 but the badger 7,taxidea taxus berlandieri7 and the kit fox1 or swift 7,vulpes macrotis neomexicana71 may well be foremost4 ,dens which have been deeply excavated by badgers are frequently seen1 and sometimes two or three badger tunnels penetrate one burrow system4 ,dens thus despoiled are probably soon reoccupied even if the original owner is captured1 and in the course of a few months the reworking of the abode obliterates the signs of destruction4 ,droppings of the kit fox show an abundance of bones of small mammals of kangaroo rat size1 among them those of spectabilis4 ,bobcats 7,lynx baileyi7 and coyotes 7,canis mearnsi7 probably are a prejudicial factor4 ,skunks may sometimes be able to surprise the kangaroo rats1 but probably not often4 ,the western horned owl 7,bubo virginianus pallescens71 the barn owl 7,tyto alba pratincola71 and perhaps others may well be among the most feared enemies1 but no special investigation of owl pellets on the reserve has been possible4 ,in #eib barn-owl pellets from ,california were found remains of #bcj kangaroo rats1 only one other rodent being represented by a larger number 7,mc,atee1 #aiba1 #beh74 ,much more information on enemies is needed4 ,the relatively low rate of reproduction 7see p4 #ah7 indicates comparative freedom from inimical factors4 ,,parasites4 ,dipodomys s4 spectabilis is regularly infested with a species of flea1 ,ctenophthalmus sp4 ,seldom or never is a specimen taken in reasonably fresh condition without some of these parasites present on its body1 though of course they desert the body of the host after it becomes cold1 and hence dead specimens left too long may be free from them4 ,the den conditions are ideal for the breeding of this parasite1 because of the great quantities of fine1 dusty1 organic refuse littering the tunnels and furnishing food and refuge for the larv4 ,as demonstrated to us by ,f4 ,c4 ,bishopp1 of the ,bureau of ,entomology1 a handful of this refuse taken from the floor of a burrow within arm's length of the entrance is almost certain to contain these larv4 ,less regularly present1 perhaps because of its different life history1 is a small tick1 ,trombicula sp4 ,at times this parasite is very common1 being present on nearly every individual rat1 and at other times specimens are difficult to find2 it appears to be more commonly present in summer and fall than at other seasons1 and is found attached chiefly to the ears4 ,no internal parasites have been detected4 ,the nocturnal and fossorial habits of the animal seem to give complete protection against a form of parasite which is very common among some other rodents of the ,range ,reserve1 notably ,lepus and ,sylvilagus4 ,nearly all rabbits are infested with warbles1 the larv of a species of bot-fly1 ,cuterebra 7family ,oestridae74 ,other small mammals also are occasionally parasitized by the ,cuterebra1 but in the handling and examination of perhaps #bjj or more individuals of spectabilis and merriami1 we have yet to find a single case of infestation by an oestrid fly4 ,,abundance4 ,one's first impression of a well-occupied spectabilis area is that a large family must inhabit each den1 but1 as previously mentioned1 we have gradually been compelled to shift from this conception to the idea of but a single animal to a mound1 except when the young are present4 ,therefore a census of the adult kangaroo rat population can readily be made1 simply by counting the mounds4 ,such a census affords at least a conservative estimate of the number of adult individuals occupying a given area4 ,the first estimates of abundance on the ,range ,reserve were from actual counts of dens on areas measured off for experimental fencing1 and gave the figure of about two mounds to the acre4 ,from time to time rough estimates were made on different portions of the pastures1 and these checked well with the above4 ,later still1 a careful count showed #cjj mounds on approximately #afj acres 7see p4 #h71 or #a4hg mounds per acre4 ,nine areas of #b acres each1 representing different environmental conditions1 were later selected in different portions of the ,range ,reserve1 and the dens accurately counted4 ,the number of dens per #b acres varied from none to a maximum infestation of #ab1 neither extreme occurring over large areas4 ,the total number of dens was found to be #dc on the #ah acres1 or an average of #b4ch dens per acre4 ,from all these estimates it may fairly be concluded that two mounds1 or two animals1 per acre is a conservative estimate for the infestation of the entire ,range ,reserve1 with the possible exception of small areas at its upper edges1 where the altitude limit of spectabilis is passed4 ,it is1 however1 impossible to estimate the area of the ,state infested with kangaroo rats1 for some large stretches of fine grassland show no kangaroo rats whatever1 while others have more than are present on the reserve2 and we have no estimates of the extent of either type4 ,,economic ,,considerations4 ,in ,may1 #ahid1 ,fisher found a ranchman at ,willcox1 ,ariz41 who complained more bitterly of the depredations of spectabilis than of those of any other mammal4 ,on the ,united ,states ,range ,reserve the food material appropriated by the kangaroo rat during good years is inappreciable4 ,there is such an excess of forage grass produced that all the rodents together make very little difference4 ,but with the periodic recurrence of lean years1 when drought conditions are such that little or no grass grows1 the effects of rodent damage not only become apparent1 but may be a critical factor determining whether a given number of domestic animals can be grazed on the area 7,pl4 ,,viii1 ,fig4 #b74 ,with two kangaroo rats to the acre 7#a1bhj per square mile71 there would be #fd1jjj animals on the #ej square miles of the ,range ,reserve4 ,if each rat stores #d pounds of grass seeds and crowns and other edible forage during the season 7and in severe seasons we find that more crowns are stored than under ordinary conditions71 a total of #bef1jjj pounds1 or #abh tons1 of edible forage are rendered unavailable to stock4 ,in dry years it is probable that this amount of forage would be of critical importance4 ,allowing #ej pounds of food a day for each steer1 the forage destroyed would be sufficient to provide for the needs of one steer for #e1abj days1 or for the needs of #ad steers for one year4 ,on a stock ranch the size of the ,range ,reserve this might mean the difference between success and failure4 ,it seems not unlikely1 therefore1 that during seasons of drought the banner-tailed kangaroo rat1 where it is abundant on the grazing ranges of the ,southwest1 may be a factor of critical importance in relation to forage production and carrying capacity4 ,it must be remembered1 moreover1 that the stored material consists largely of seeds1 so that this loss is of greater importance than would be the case were it ordinary forage4 ,some of the range grasses of this region found in greatest quantity in the stored material depend in large part1 under certain conditions1 upon seed reproduction4 ,rehabilitation of a depleted range after severe drought and consequent close grazing and trampling is retarded by the heavy toll of seed taken by the kangaroo rats4 ,,control4 ,kangaroo rats may be easily eradicated by the use of the poisoned grain used for prairie-dog control by the ,biological ,survey and the ,university of ,arizona ,extension ,service4 ,this can be obtained by application to the ,state representative of the ,biological ,survey or to the local county agricultural agent1 or may be mixed as follows3 ,formula for poisoned bait4--,dissolve #a ounce of strychnine sulphate in #a-a_/b pints of boiling water4 ,add #a heaping tablespoonful of gloss starch1 previously mixed with a little cold water1 and boil until a clear paste is formed4 ,add #a ounce of baking soda and stir to a creamy mass4 ,add #a_/b ounce of glycerine and #a_/d pint of corn sirup and stir thoroughly4 ,pour over #af quarts of rolled barley and mix well until every grain is evenly coated4 ,allow to dry before using4 ,in bushel quantities use as above directed1 #b ounces of strychnine1 #b ounces of soda1 #a ounce of glycerin1 #a-a_/d ounces of starch1 #a-a_/b quarts of boiling water1 and #e_/h pint of corn sirup4 ,scatter poison1 when the natural food of the kangaroo rat is scarce1 on clean hard places near the holes1 #a quart to #ej holes4 ,if powdered strychnine alkaloid is used1 prepare the hot starch paste first4 ,then sift strychnine and baking soda1 previously thoroughly mixed1 into the hot starch paste and stir to a creamy mass4 ,proceed as in the above directions with sirup1 glycerin1 etc4 ,use this poison within five days after mixing or retain in air-tight containers4 ,caution4--,all poison containers and all utensils used in the preparation of poison should be kept plainly labeled and out of reach of children1 irresponsible persons1 and live stock4 ,a spoonful of the poisoned grain scattered about the used entrances of a mound is sufficient1 and prebaiting is not necessary1 as with prairie dogs4 ,a word of caution should perhaps be offered in connection with control measures4 ,as man has come to occupy a greater portion of the earth's surface1 and as he has become more and more the master of his environment1 he has inevitably disturbed the relationships of the birds and mammals about him1 has upset the balance of nature4 ,if he kills the carnivorous species because of their depredations on game and live stock he must be prepared to cope with the increased hordes of rodents which feed on vegetation and on which the carnivorous animals act as a check4 ,if he destroys the rodents1 he may remove the checks on certain noxious plants or insects4 ,one control measure often necessitates the adoption of another4 ,this is not to argue against control measures1 for if our harmful species were not controlled1 agriculture in many sections would be impossible4 ,control measures1 however1 should be scientifically founded and applied4 ,the indiscriminate slaughter of supposedly harmful species of birds and mammals in the guise of benefiting agriculture may do far more harm than good4 ,many of the species which do some harm do far more good4 ,the exact status of each suspected species should be carefully determined through an adequate scientific investigation4 ,if the species is condemned1 sound control measures should be thoroughly applied4 ,in grazing districts or in areas devoted to intensive agriculture the death sentence should probably be passed on the banner-tailed kangaroo rat4 ,it should be recalled1 however1 that this is the largest and one of the handsomest of all its family1 and that it is one of the most characteristic and interesting of all the desert fauna2 where extensive grazing or agricultural operations are not undertaken1 therefore1 we feel that the kangaroo rat should be let alone1 unless its presence threatens infestation of valuable agricultural or grazing lands4 ,,summary4 7#a7 ,kangaroo rats may be separated with ease from all other mammals2 the long tail and short and weak fore feet separate them from the pocket gophers2 the white hip-stripe distinguishes them from the pocket mice4 ,the decidedly larger size and the white-tipped tail separate ,dipodomys spectabilis spectabilis and ,d4 deserti from ,d4 merriami and ,d4 ordii4 ,the darker color and vividly contrasted black-and-white tail of spectabilis distinguish it from deserti4 7#b7 ,dipodomys s4 spectabilis occurs in the open arid country of portions of the ,lower and ,upper ,sonoran ,zones of ,arizona1 ,new ,mexico1 ,texas1 ,sonora1 and ,chihuahua4 ,it lives in harder soil than does deserti1 and builds more conspicuous mounds4 7#c7 ,there is no evidence of intergradation or hybridization between spectabilis and deserti4 7#d7 ,dipodomys s4 spectabilis is nocturnal2 it is gentle1 and does not offer to bite when taken in the hand2 is silent for the most part2 active2 somewhat sociable with its fellows1 but fights in defense of its food stores2 progresses chiefly by leaping2 signals by a drumming or tapping on the ground with its hind feet4 7#e7 ,the breeding season of spectabilis begins in ,january and continues into ,august4 ,whether more than one litter is raised in a single season is unknown4 ,the number of young in each litter varies from #a to #c1 averaging #b4 7#f7 ,dipodomys s4 spectabilis does not hibernate1 but provides food stores1 mostly seeds1 for use during seasons when food would be otherwise unavailable4 ,storage in each den varies in quantity from #e grams 7about #a_/f ounce7 to #e1gej grams 7#ab4fg pounds74 ,materials stored include several important forage plants2 for example1 various species of ,bouteloua and ,aristida1 with ,b4 rothrockii 7crowfoot grama7 the most important4 ,accessibility and abundance of different plants have much to do with the kinds of storage found4 7#g7 ,the dens of spectabilis are the most notable of all kangaroo rat dwelling places4 ,they range from #f inches to #d feet in vertical height1 and from #e to #ae feet in diameter4 ,here the kangaroo rat has its home1 shelter1 and food-storage chambers4 ,within the den is found a tortuous network of burrows1 with many storage and some nest chambers1 the whole arranged so as to be two to four stories high4 7#h7 ,dipodomys s4 spectabilis is not of great economic significance1 except locally1 in ordinary seasons4 ,during periods of extreme drought it may be of critical importance on grazing areas from the standpoint of the carrying capacity of the range4 7#i7 ,kangaroo rats are easy to poison by following the same formula as that used by the ,biological ,survey for destroying prairie dogs4 7#aj7 ,in many places unsuited to extensive grazing or agriculture spectabilis does no appreciable damage4 ,it is one of the most interesting of all the rodents peculiar to our ,southwestern deserts1 and should not be molested except where it is destructive4 ,,bibliography4 ,,allen1 ,j4 ,a4 #ahie4 ,on a collection of mammals from ,arizona and ,mexico1 made by ,mr4 ,w4 ,w4 ,price1 with field notes by the collector4 ,bull4 ,amer4 ,mus4 ,nat4 ,hist41 vol4 #g1 art4 #f1 pp4 #aic-beh4 #ag figs4 in text4 ,,babcock1 ,s4 ,m4 #aiab4 ,metabolic water3 ,its production and rle in vital phenomena4 ,research ,bull4 ,no4 #bb1 ,univ4 ,wisconsin ,agr4 ,exp4 ,station1 pp4 #aei and #agj1 ,march4 ,,bailey1 ,v4 #aije4 ,biological survey of ,texas4 ,north ,amer4 ,fauna ,no4 #be1 ,biol4 ,surv41 ,u4 ,s4 ,dept4 ,agr41 pp4 #bbb1 #af pls41 #bd figs4 in text4 ,,clements1 ,f4 ,e4 #aije4 ,research methods in ecology4 ,lincoln1 ,univ4 ,pub4 ,co41 pp4 xvii1 #ccd1 #he figs4 in text4 ,,griffiths1 ,d4 #aiaj4 ,a protected stock range in ,arizona4 ,bull4 ,no4 #agg1 ,bur4 ,plant ,ind41 ,u4 ,s4 ,dept4 ,agr41 pp4 #bh1 #f pls41 #a fig4 in text4 ,,grinnell1 ,,joseph4 #aiba4 ,revised list of the species in the genus ,dipodomys4 ,journal of ,mammalogy1 vol4 #b1 ,no4 #b1 pp4 #id-ig1 ,may #b4 ,,mcatee1 ,w4 ,l4 #aiba4 ,farm help from the birds4 ,in ,yearbook of the ,u4 ,s4 ,dept4 ,agr4 for #aibj1 pp4 #bec-bgj2 unnumbered figs4 in text4 ,,merriam1 ,c4 ,h4 #ahij4 ,description of three new kangaroo rats1 with remarks on the identity of ,dipodomys ordii of ,woodhouse4 ,in ,north ,amer4 ,fauna ,no4 #d1 ,div4 ,ornith4 and ,mamm4 7,biol4 ,surv471 ,u4 ,s4 ,dept4 ,agr41 #da-di4 ,,nelson1 ,e4 ,w4 #aiah4 ,smaller mammals of ,north ,america4 ,nat4 ,geog4 ,mag41 vol4 #cc1 ,no4 #e1 pp4 #cga-dic2 numerous unnumbered figs4 and colored pls4 in text4 ,,additional ,,copies ,,of ,,this ,,publication ,,may ,,be ,,procured ,,from ,,the ,,superintendent ,,of ,,documents ,,government ,,printing ,,office ,,washington1 ,d4 ,c4 ,,at #ae ,,cents ,,per ,,copy