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Quadruplets in mule deer.

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Department of Zoology, Montana State University, Missoula, Montana
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
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.
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.
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
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 rneriibratie w a s laid out it rncasiired 65 cni in Iciigih in contrast
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
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
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.
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.
C. W. 1949 Tooth development and wear as criteria of age
in white-tailed deer. J . Wildl. Manng., 2 3 : 195-216.
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quadruplex, deer, mule
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