QUADRUPLETS I N MULE DEER1 HOWARD S . SEARS AND LUDVIG G. BROWMAN Department of Zoology, Montana State University, Missoula, Montana ONE FIGURE INTRODUCTION Female deer of several ages were collected every month of the year as part of an investigation on the female Rocky Mountain Mule deer (Odocoileus hemouzius hernouzius) population of the National Bigon Range, Moiese, Montana. The discovery of 4 normal fetuses in a pregnant doe in this series, killed in January, 1954 is so unusual that it was thought worth reporting. Twinning in mule deer is a common phenomenon for 299 out of 569 does had twin fetuses o r twin fawns as reported by Robinette and Gashwiler ('50). However triplets are encountered only infrequently, for these same authors report only 5 out of 569 mule deer pregnancies as having triplets. The present report is the first report of polyzygotic quadruplets in the mule deer linown to the authors. MATERIAL The female deer were shot and autopsied in the field. The entire reproductive tracts were dissected out, cut open t o permit better fixation, and the tagged specimens were placed in 10% formalin. All analyses, weights, and measurements were made in the laboratory on the preserved material. Age determinations of the adult does were based on teeth analyses according to the technic developed by Reveringhaus ( '49). This investigation was made possible through the cooperation of the Fish and Wildlife Service, The Montana Fish and Game Department, and the Montana Coopcrativc Wildlife Research Unit. 335 336 HOWARD S. SEARS A N D LUDVIG G. BROWMAN Fifty pregnant mule deer were autopsied in the field during January, 1954. Migration of fertilized ova or possibly of' unimplanted blastocysts from one uterine horn to the other is apparently a normal occuri-ence i n mule deer. Examination of the uteri and ovaries of single pregnancies with only a single recent corpus luteum showed that 10 of 17 fetuses were in the ipsolateral horn and 7 in the contralateral horn. Further substantiation for the fact of transmigration is that deer with two corpora in only one ovary had the two fetuses equally spaced i n either uterine horn and no uterine horn contained both fetuses (15 cases). Where the fetuses present were reduced l o one, but with two corpora in one ovary, there were two cases with ipsola teral single implantations, and one case of a contralateral implantation. Ovaries from three pregnant does had more than two recent coiyor'a Intea. (Measurements of the 50 ovaries from the right side collected in ,January averaged 17.8 inm X 12.6 mm x 7.4 mm. The left ovaries in this series of 50 pregnant does were almost identical in size : 17.9 X 12.1 x 7.4 mm.) Dcer no. 7 h had three corpora in the right ovary and one in the lcft ovary. However the 4 young male fetuses were evenly d i s t i 4 ~ u t c din the two uterine horns. Deer no. 39 A had two corpora in each ovary but only one fetus was present i n each horn. Dcer no. 36 d had one corpus in the right ovary and two in the left ovary, with one male fetus in the right horn and two females in the left horn. Incidentally it is of interest to note that 9 out of 23 singleton fetuses v e x found in the one to two year old class with no other year age class through 10 years having more than 4 singletons. Fifteen out of 25 multiple pregnancies (twins, triplets, etc.) were produced in the two to 4 p a r classes, with only two sets of twins in the one to two year class. The sex ratio of all fetuses collected was 40 males to 37 females. IIule deer doe no. 7 A , approximately 4; pears old, was estimated to have been pregnant f o r about two and one-half months when shot. She had three recent corpora lutea in the riglit ovary aiitl oiic coiyus lntcluni in tlir left ovary. Howevey, tlic 4 frtuses rvei*e equally distribntecl o n the two sides of tlic utcrinc septimi. The 4 males a r e believed to liavc dcvcloped frotii 4 separate eggs as a imult of rnnltiplc ovulation. Thc i\vo rrialcs in thc right liorn wei-ci ('-R 80 atid 87 niin rcs l ) ( d v c l y , arid the tivo malw in the left 1101-11 were C-R 82 alld 86: 111111. Tlie usual iiunibcr of caruiwles i i i tlic ferrialc niul(1 tlcer utcrus has I)ccw detorniiticd by 11s to be 6, althougli W P l i a ~ counted as rriatiy a s 9 caruncles in a pi-cgtiant uterus, and as f c w as 5 in a nori-gravid u t e i u . Acccsso1.y carunclcs appear to derclop largely, hut not exclusirely, o n the utcrinc septum during pregiiancy and to disappear sliortlp after parturition. The sniallcst fetus in the 1-iglithorn occupied only one carariclc n-hereas the ot1ieI- tl1rtv ft~tuscs\vPre cacli Rdllel*ellt to two caruncles. The amnion and cliorio-allaiitoic merri1)raiies of the srnaller ant1 lighter i n d c fetus 110. 1 mere corripletely indcpetidc~itof tlic frtal iiieriibraiies of tlie other three sibs. Fctus no. 1 had only one placentornc located in thc> distal cxteiisioii of thc right uterine horn. Tlic otlicr three male fetnscs had indelwiidmt amniotic rricrrihi-anes with only incomplete fusioii of ainniotic iiicinbi.ancs hetween fetuses 2 and 3, arid 3 and 4. How(.c.vcr.there was a complcte and contiiruous coninion chorioallantoic nicrn1)raiic beginning in the right horn, passing through the Imiy of the uterus 1 ) c y i i t l tlic septum, occupying all of the k f t uterine horn arid enclosing fetuses no. 2, 3, and 4. This coninion chorio-allnritoic memhi*anc shared the reriiaining 6 caruriclcs. Tlw 1)lood siqq)lp of' tlicl plactwtomcs lvas esscntially inclcpendent of oiie aonther as far as could he drtei-mined on tlie field prc~serreclmaterial. Blood vessels of the majoi- extra-embryonic 1)loocl supply f r o m tlic cotyletloiis of fetus no. 2 occupied all of cai~uricles 2 and 3, cotyledons froni fetus no. 3 occupied caruncles 4 a i i c t 5, axid the cotyledons from fetus no. 4 pciictratcd all of caimiclcs 6 and '7. T h e n the coiiirrioii clioi.io-allaiitoic rneriibratie w a s laid out it rncasiired 65 cni in Iciigih in contrast 338 HOWARD S. SEARS AND LUDVIG G. BROWMAN to the same membrane of fetus no. 1 which measured only 15 em in length. Mule deer doe no. 36A, also approximately 49 years old, was estimated to have been pregnant for about three months when she was shot. Data are included on her triplets and reproductive tract for comparative purposes. The three fetuses, Figure 1 which included two males (C-R 120 and 129 mm) and one female (C-R 135mm) are believed to have developed from three separate eggs. There was one corpus luteum in the right ovary and two corpora in the left ovary. There was no fusion between the amniotic sacs, but again there was a common chorio-allantoic membrane enclosing the three fetuses. However major extra-embryonic fetal blood QUADRUPLETS I N M U L E DEER 339 vessels of placeiitomes for each fetus tended to concentrate in separate cotyledons, Cotyledons from fetus no. 1 occnpied a11 of caruncles no. 1, 2, and 3 while cotyledons for fetus no. 2 occupied only caruncle no. 4. Extra-embryonic blood vessels for fetus no. 3 and its cotyledons occupied all of caruncles no. 5 and 6. No placentomes had developed n conjunciton with the caruncle on the uterine septum at this stage of pregnancy. The authors have the impression after having examined a number of multiple pregnancies in the mule deer that the smaller fetuses a r e those which have developed in conjunction with only one placentome. SUMMARY A pregnancy involving 4 polyzygotic fetuses is reported in the mule deer for the first time. The fetuses were evenly distributed in the uterus of the pregnant doe. Although all 4 of the fetuses were males it is believed that they represent 4 different fertilized eggs. LITERATURE CITED ROBINETTE, W. L., 9 N D J . 8. GASHWILER1 9 X Creediiig season, productivity. and fawning period of the mule deer in TTtah. J. of Wildl. Manag., 2 4 : 457-469. SETERINGHAUS, C. W. 1949 Tooth development and wear as criteria of age in white-tailed deer. J . Wildl. Manng., 2 3 : 195-216.