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Fertility and twinning in Canadian reindeer

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Abstract and Figures

This study was carried out from 1976 to 1981 on the Mackenzie Delta reindeer herd with the co-operation of the owners, Canadian Reindeer Ltd., Tuktoyaktuk, Northwest Territories. The reproductive organs of 4050 female reindeer (Rangifer tarandus) were collected at slaughter. The pregnancy rates averaged 99.5% of the females examined. In the years 1978 and 1981, 24.7% (713) of the animals were carrying twins, as compared to a twinning rate of 0.4%) observed for the intervening years. Nineteen animals were not pregnant. Of these, 14 were emaciated with no gross pathology* of the reproductive tract. Five females had either a mummified fetus or uterine adhesions preventing a viable pregnancy. Estimated fawn survival rates from birth to June varied from 51.7 to 95.7%. Fawn survival from June to yearlings of June the next year varied from 51 to 86.4% as determined by count at roundup. Increment averaged 15.8% per year after a slaughter of 13.4% of the herd yearly.
Content may be subject to copyright.
Fertility
and
twinning
in
Canadian reindeer
G.
F. Godkin
1
Abstract:
This study
was
carried
out
from
1976 to 1981 on the
Mackenzie
Delta
reindeer herd with
the
co-operation
of the
owners, Canadian Reindeer Ltd., Tuktoyaktuk, Northwest Territories. The reproductive
organs
of
4050 female reindeer
(Rangifer
tarandus)
were
collected
at
slaughter. The pregnancy
rates
averaged
99.5%
of
the
females
examined.
In the
years
1978
and
1981, 24.7%
(713) of the
animals
were
carrying twins,
as
compared to
a
twinning
rate
of 0.4%) observed for the intervening
years.
Nineteen animals
were
not pregnant.
Of
these,
14
were
emaciated with
no
gross
pathology* of
the
reproductive tract.
Five
females
had
either
a
mummified
fetus
or
uterine adhesions preventing
a
viable pregnancy. Estimated fawn survival
rates
from
birth
to
June
varied
from
51.7 to
95.7%. Fawn survival
from
June
to
yearlings
of
June
the
next
year
varied
from
51
to
86.4%
as
determined
by
count
at
roundup. Increment
averaged
15.8% per
year
after
a
slaughter
of
13.4%
of
the
herd
yearly.
Key
words:
reindeer, pregnancy
rates,
twinning, Canada, fawn survival, recruitment,
Arctic.
'Canada Agriculture, Box
1600,
Innisfail, Alberta, Canada
TOM
1A0.
Rangifer,
Special
Issue
No.
1, 1986: 145 - 150
Introduction
Domestic
reindeer, transplanted
to
Alaska
in
1891, came
from
two
Asian
stocks,
a
large
form
presumably
from
forest reindeer stock
and a
small
form
presumably
from
a
tundra sub-
species
(Banfield,
1961).
A
herd
of
some
3000
reindeer was purchased
in
Alaska in
1929 by the
government of Canada and, after an epic journey
of
63
months,
was
delivered
to the
Mackenzie
Delta
region
in 1935
(Scotter,
1978).
The
larger
form,
which calved
in
April,
was
selected
for
introduction
to
Canada (Porsild,
1954).
The
following
is a
report
of my
evaluation of
reproductive
rates,
occurrence
of
twinning,
and
fawn
survival
in the
Mackenzie
Delta
herd
from
1976
to 1981,
based
on
examination
of
female
reproductive
tracts
obtained
from
reindeer
slaughtered either
in
November
or in
Februa-
ry
March
of
each
year
and annual records of
sex
and age
composition
of the
herd obtained
during
June
roundups.
Study
herd
The
reindeer
are
managed on
an
open herding
basis
on the winter
range;
that is, the herd
is
kept
in
a
certain region selected
by the
owner, but
no
attempt
is
made
to
keep
the
herd
as one
group.
The
summer
range
is
the Tuktoyaktuk Peninsula
where no herding
is
required except for periodic
surveillance
by
aircraft.
As the
herd
migrates
southward down
the
peninsula
in the
fall,
it is
met
by
the herders and guided to the grazing
area
selected for that winter. The herd
is
kept under
surveillance
by
aircraft
and
snowmobile
to
prevent straying and to check for wolves.
During
the winter the herders
use
snowmobiles
to
bring
straying animals back
to
the vicinity of the main
herd.
The
major slaughter
is
conducted between
18
February and
5
March
in
order
to
utilize
the ice
road
to
ship
the
meat
to
southern markets.
Occasionally
there
has
been
a
small inspected
slaughter
in
November, mostly
for
northern
Rangifer,
Special
Issue
No.
1, 1986 145
markets. The slaughter
site
is
moved each
year
to
an
area
where there is enough forage to sustain
1500 to 2000 reindeer for two weeks.
About
1500
reindeer
are
separated
from
the
main herd and
brought
to the
slaughter
area.
Selected animals
are slaughtered, that herd
is
moved
away
and
another group
is
brought in.
Nutrition
is at its
lowest
ebb and
fawning time
is
near,
so the
slaughter period
is
also the most critical time of
year
for
the
reindeer. Therefore,
an
attempt
is
made
to
utilize
a
sub-unit
of
the herd for only
2
days
to
minimize
the
stress.
After
slaughter
the
whole herd
is
guided
towards
the
fawning
area,
so as to
arrive
by
fawning
time. Fawning
takes
place
in an
area
protected
by
hills
from
the
cold
spring winds.
The
first fawn
will
be
born
30
March
to
2
April
and fawning
will
be general 10
days
later.
Most
of
the
fawns
are
born
by the
middle
of
May
although
an
occasional fawn may arrive
as
late
as the middle of August.
Most
of the fawns
born
late
probably
do not
survive
the
following
winter.
Immediately after fawning the herd begins
to
migrate towards the Tuktoyaktuk Peninsula for
summer
range.
The migration
is led by
older
females
who fawned
early
or
lost their fawns,
with
the majority
of
the bulls
following
1
or 2
days
later. The remainder
of
the herd
is
strung
out
for 100 km with the
females
with
late
born
fawns and the
yearlings
bringing up the
rear.
The
leaders
reach
the tip of
the peninsula about
20
June, with
the
last
ones arriving
2
weeks
later.
The
reindeer have to summer on the
Arctic
coast
for
minerals
and
possibly also
to
avoid insect
harassment, which they
do by
standing
in the
water or lying on sandy
beaches.
Materials
and
methods
Examination
of reproductive tracts
Between 1976 and 1981, 5700 reindeer
were
examined
at
slaughter under the
auspices
of the
Food
Production
and
Inspection Branch,
Agriculture
Canada.
Most
of
the slaughter
was
done
in the
month
of
February each
year,
although some small
slaughters
were
done in
November.
The
female reproductive organs
were
placed
to
one side
by
the butcher during eviseration
so
they could
be
counted and examined
at
the end
of
the
day's
kill.
Data recorded included
(1)
the
number of pregnancies, (2) the number of
fetuses
per pregnancy (3)
stage
of gestation, and (4)
gross
reproductive pathology.
Since
1976 the
herd
has
been rounded
up
beginning
about 18
June
each
year
by helicopter
and corralled under supervision
of
Agriculture
Canada.
In
1976
and
1977
the
roundups
were
incomplete,
but
from
1978 to 1981 for all
practical
purposes
the
complete reindeer herd
was corralled.
The
spring roundup
is
conducted
to cut the
velvet
antlers
from
the
bulls
and
females
for¬
export.
All
the animals
were
run through a chute,
the fawns
are
tagged
with color coded
tags
for
the
year
of
birth,
females
to be
slaughtered
the
following
winter
are
marked with
ear
ribbons
and bulls which
are
surplus
or
inferior
for
breeding purposes
are
castrated.
The
yearling
females
with fawns
at
the spring
roundup
were
counted
in
with
the
mature
females
for the
years
under review.
The
percentage
of yearling
females
producing fawns
each
year
(bred
as
fawns) was not determined.
The
numbers
of
major
segments
of
the herd
were
recorded
so the
number
of
yearling bulls
and yearling
females
without fawns allowed
an
estimate
of survival
to
1
year
of life of previous
year's
fawns.
Results
Between 1976 and 1981, 5700 reindeer
were
examined
at
slaughter, mostly
in
February
of
each
year.
All but 19 of the 4050 2-year-old and
over
female reindeer examined
at
slaughter
from
1976
to
1981
were
pregnant with viable
fetuses
(99.5%).
Five
of the 19
females
exhibited
gross
reproductive pathology: three
had
uterine
adhesions and two each
a
mummified fetus. The
Table
1.
Annual
reprod'
uctive
rates
of
female rein-
deer
o
btained
at slaughter
(Feb.-Mar.),
Mackenzie
Deli
ta herd, NWT, Canada.
2
+
-yr-o
Id
females
sampl ed
Year
N
%
pregnant
%
single fetus
%
twin
fetuses
1977
357
99.2
99.2
0.8
1978
932
99.6
73.8
26.2
1979
481
99.4
99.6
0.4
1980
231
98.7
99.6
0.4
1981
2042
997
76.9
23.1
146
Rangifer, Special
Issue
No.
1, 1986
Table
2.
Proportions
of
females
and
fawns
in the
annual
June
roundup
of
Mackenzie
Delta
herd
reindeer,
NWT,
Canada.
Fawns/
females
11
0/
100 females
Year
sample"
Hyr
24-yr
Fawns
Hyr
2+yr
1977
5205
45.0
36.9 35.3
78.5
95.7
1978 8245
47.7 37.2
35.0
73.4 94.1
1979
9855
43.2 32.4
24.2
56.2 72.0
1980 12745
46.5
38.5 24.3
52.4
63.2
1981 10879
41.9 34.8 21.5
51.3
61.8
a
All
reindeer
corralled.
b
The category
1
+-yr females includes all females
1-yr
or
older;
and the
category
2 + -yr'
females includes
all
females 2-yr and
older,
plus yearling females
with
calves
(excludes
only
yearling females
without
calves).
remaining
14
were
not
pregnant
but
showed
no
gross
reproductive pathology (emaciation, either
from
old age or
injury, probably
had led to an
anestrous
condition
during
the rut).
The annual
rate
of
pregnancy (with
a
viable fetus
or
fetuses)
averaged
99.5%
(±0.4%
S.D.).
Only
seven
2 +
-year-old
females were
exami-
ned
at
slaughter
in 1976: all
were
pregnant, each
with
a
single fetus. Relatively
large
samples
of
2H--year-old
females were
slaughtered
from
1977
to
1981.
Over
the
whole study period
17.8% of
the mature
females
slaughtered
were
pregnant
with
twins.
In 1978 26.2% and in 1981, 23.1%
of
the
females
at
slaughter
were
carrying twins
(Table
1). In the
other
3 years
under review
the
average
twinning
rate
was 0.56% per
year.
From
1977 to 1981 the
fawns
aged
about
2
months made
up 21.5 to 35.4% of
the herd with
Table
3.
Reindeer
production
and
survival
to the 2nd
month
of
life,
Mackenzie
Delta
herd,
NWT,
Canada.
No.
females
producing
1
Fawns
Fawns
alive
%
early
fawn
Year
Single»
Î
Twins
born
mid
June
survival
1977
1889
15 1919
1836
95.7
1978
2253
800
3853
2884
74.9
1979
3286
13 3312
2389
72.2
1980
4824
19
4862
3102
63.8
1981
2903
872
4647
2338
50.3
a
Calculated
from
reproductive
rates
given
in
Table
1.
Rangif er,
S p
e e
1
a 1
1
s s
u c No.
1,
198 6
an
average
of 26.7%
(Table
2). The
number
of
fawns per
100
females
ranged
from
51.3 to
78.5%
averaging
64.9%.
Since the yearling
females
with
fawns
are
counted
as
adults,
all the
female
yearlings
have been included in the female counts
(Table
2), for
comparative purposes. Females
comprised
from
41.9 to 57.7% of the
herd
sample, averaging
44.7%.
The
yearling
females
without
fawns comprised
from
16.9 to
23.4%
of
the female population with
an
average
of 19.3%
(Table
3).
Fawn survival
to 1-year of age
averaged
64.7%
(Table
4).
There
has
been
an
average
slaughter
of 13.4% of the
herd
yearly
from
1977 to 1981 and
increment
has
still
averaged
15.8% per
year.
The size predicted
for
the total herd
in 1980,
calculated
from
these
Table
4.
Reindeer
fawn
survival
from
birth
to the 2nd
June
of
life,
(13-14
months),
Mackenzie
Delta
herd,
NWT,
Canada.
Herd
Number
%
% fawns
sample
of
yearling
%
surviving
Year
(less
lawns)
yearlings
recruitment fawns' to l-yr
b
1977
36.9
1978 5361
1238 23.1
46.7 67.4
1979 7466
1721 23.1
33.6 59.67
1980 9643
2064 21.4
38.1 86.4
1981 8541
1582 18.5
42.7 51.0
a
Percentage fawns equals estimated
number
of fawns
born
(Table
3) as
proportion
of
herd
sample (Table
b
Calculated
by
dividing
the
number
of
yearlings
by
the
number
of
live
fawns
from
the
preceding
vear.
Table
5.
Herd
numbers calculated
from
increment
15.8%
yearly.
Year
Calculated
Herd
Actual
Count
1974
5000
1975
5795
1976
6716
1977
7784
5205
1978
9022
8245
1979 10457
9855
1980
12120
12745
1981
14047-
1
10879
1982
12598
1983
14588
a
Reduced
by
all large slaughter and
a
heavy neo-natal
and
lawn
loss.
147
numbers,
was at
variance
with
the
actual count
at
round
up by—5% (Table 5).
In
1981
die herd
numbered
22.6% below
the
calculated number
(Table
5)
because
of
a
large
female slaughter.
As
well
there
was the
lowest fawn survival
in
both
the new
born
fawns and
the
coming
yearlings of
all
the
years
under study (Table
3).
Discussion
The
pregnancy
rates
observed
in
this reindeer
herd
(Table
1)
seem
to be
higher than those
reported
in
other
Rangifer tarandus
populations
in
the
world
(McEwan,
1963;
Michurin,
1967;
Kelsall,
1968;
Dauphine,
1976).
The
rates
reported
here were based
on
counts
of
pregnancies
at
slaughter, mainly
in
females over
6
years
old. These
rates
may
have been slightly
higher than
the
rates
for the
population
as a
whole,
since
the
majority of does
in
the herd
are
under
4
years
of age and are,
therefore,
least
likely
to be
pregnant.
However,
the
error
appears
to be
slight, since
in
1977
the
birth
of
1920 fawns
was
predicted
on the
basis
of
projected
observed pregnancy
rates
at
slaughter,
and
the
actual count in June
was
1863 (Table
3)
for
an
error
or a
fawn loss
from
all
causes
of
4.3%.
In
Alaska
fawn crops
from
50 to
60%
of
the adult does
are
usual,
but
under ideal
conditions
fawns crops
may
reach
85 to 95%
(Palmer,
1934).
A
fawn crop
of
51.3%
in the
worst
year
(1981)
(Table
2) is
not below
normal
for
other populations.
There
was
no
way to
determine how many of
the females
with
fawns were just
a
year
old.
In
Alaska,
up
to
5% of
yearling females have been
observed
with
fawns (Hadwen, 1942).
Many
of
the yearlings
with
fawns appear
to
have fawned
later than
the
main herd judging
by
the
size and
apparent
age of the
fawns
in
June.
Yearling
females have been observed fawning
as
late
as 21
June.
The
fawns of yearlings
are
weaker
at
birth
and
the young mothers
do
not have
as
much
milk
as
the mature females, thus increasing the fawn loss
from
yearlings.
However
this loss
is
partly
balanced
by the
more careful tending
of a
fawn
by
a
yearling cow than
by
an
old cow (Hadwen,
1942).
When
herding
by
helicopter
the
young
females
will
drop behind
with
the
fawn when
it
is exhausted, whereas
the
old females
will
leave
the fawn
to
rejoin
the
herd.
Twinning
has
been reported
in
reindeer
and
caribou
by
Palmer
(1934)
and
Nowosad
(1973);
for
captive barren-ground caribou
( R. t.
groenlandicus)
by
McEwan
(1971);
and
free-
ranging
woodland caribou
(R. t. caribou) by
Shoesmith
(1976).
Twinning
varied markedly
from
nearly
no
production
of
twins
in 3-yr
(mean
= 0.5% ±
0.23% S.D.)
to
about 25% of the pregnancies
in
2-yr
(mean=24.7%±2.19%
S.D.).
The
high percentage
of
females observed
with
twin
fetuses
at
slaughter
in
1978
and
1981
has
never been reported before
in any
Rangifer
tarandus
populations.
Forty
percent
of
barren-
ground
caribou
in
the
wild
produce
two ova
at
one
cycle,
but no
evidence
of
advanced
development
of a
second embryo
has
ever been
found
(McEwan,
1963).
If
dual ovulation also
occurs
commonly
in
reindeer, then
a
trigger
mechanism
could
be
postulated
which
operates
on
occasion
to
allow
the
development
of the
second
embryo.
Variable
factors during
the
period
of
study
included
weather
and
antler removal.
Climato-
logical
data for
the
Tuktoyaktuk
area
show that
precipitation
was
slightly higher than
normal
in
late
June and early July, 1977 and again
in
1980.
This
increased precipitation
may
have produced
more
forage earlier in
the
season
by
drawing
the
frost
sooner
and
thus increased body
condition
to
stimulate multiple ovulation
and
implanta-
tion.
In
caribou,
full
recovery
of fat
deposits
during
the
summer
is
critical
to
reproduction,
growth,
and
winter survival (Dauphine, 1976).
The
velvet antlers were removed
from
the
reindeer herd
for the
first time
in
1977.
When
a
high
rate
of
twin
fetuses
was
found
at
slaughter
in
the
following
spring, the possibility of a casual
relationship
between antler removal
and
twin-
ning
was
considered.
However,
twin
pregnan-
cies occurred
at
what
appears
to
be the usual
rate
in
the
next
2
years,
despite
the
annual antler
harvest,
and
increased
in
frequency again
in
1981.
The only effect antler removal
may
have
on
twinning
is the
stimulation caused
by
roundup
which
promotes early shedding
of
the
winter
coat,
which
in
turn
may
enhance early
fattening.
Neo-natal
mortality (between
March
1 and
June 30) estimated
from
pregnancy
rates,
(fawns
dropped
before
April
1)
due
to
abortion, lack of
milk,
abandonment, stillbirths, (fawns
born
after
April
1 that
are
dead
or so
weak they
are
unable
148
Rangifer,
Special Issue No.
1, 1986
to
move) weak fawns,
and
inclement weather
(Table 3) varied
from
4.3%
in
1977 to 49.7%
in
1981.
In 1981 the snow depth
at
the end of
April
was 66 cm
as
compared
to
55 cm in 1980, when
mortality
was
36.8%.
In the
other
years
under
study the snow depth was 15 to 33 cm,
with
fawn
loss varying directly.
In
1978 there were many
females
with
twins
at
the roundup, and the snow
depth
at
the end of
April
was 23 cm, whereas in
1981 only two females were seen
with
twins.
Predation
is not a
major factor
in
fawn
mortality
as the
herd
is
under constant
supervision
after the first heavy snowfall
in the
fall
until
the end of May. The
stress
of herding,
prolonged
food
deprivation, and hazing during
the slaughter period is probably one of the major
causes
of fawn mortality, affecting
both
pregnant
females
and
coming
yearlings.
In 1981 the
slaughter
was
terminated early because
of
excessive
fat
vascularization
from
the rapid loss
of
body
condition.
After
the
harassment
had
been almost continous for
3
weeks, subsequent
fawn
losses were heavy
from
March
until
the
middle
of
May. That
year
the herders reported
many abortions and
stillborn
fawns. The fawns
surviving
at
roundup were "smaller than norma!
with
very little antler growth. The females
with
the most
fat
reserves appeared
to
have the best
rate
of
fawn survival. Whether
the
early fawns
were aborted or the gestation time was prolonged
could
not be
determined.
A
high plane
of fat
reserves and good
nutrition
decreases
gestation
time
(Krog,
1980).
Since 1981
the
slaughter procedure
has
been
changed so that the animals to be slaughtered are
corralled
and the rest of the herd
is
not harassed
all
day.
This
reduces the
stress
on all the animals
and
helps prevent
the
loss
of
critical
body
tat
reserves
in
the fawns and females.
Fawn
mortality
until
the end of June
seems
to
be directly related
to
the snow depth
at
the end
of
April
and the
amount
of
harassment
at
slaughter.
Fawn
losses
from
stress
of
handling
start in
March
and continue, whereas losses
from
weather occur
oniv
at
birth
or
shortly after.
Twins
most
years
are a
disadvantage because of
poor
survival
rates
if
conditions
are not idea!, and
thus they
cause
an
increased net fawn loss.
The
percentage of fawns surviving to one
year
oi
age
(Table
4) is
inaccurate
to the
extent thai
yearling females
with
tawns
are
counted
as
adults.
Also
small groups
of
just yearlings
a:
roundup
are not
brought
m tor
count: because
EaitgifeiS
Special
Issue No.
i, 1986
they have
no
antler
of
commercial value.
The
actual number of yearlings
is,
therefore,
greater
than
the value given
in
Table
4.
The
survival of fawns
from
June
to
yearlings
would
be
greatly enhanced
if
coralling
and
slaughter procedures were
modified.
Too many
fawns
are
separated
from
the females during the
corralling
and handling procedure for too
long
with
some never getting back together. The fate
of
these
fawns
is
unknown.
Fat
reserves
in
February
are
excellent on
the
older
females while the fat reserves on the fawns
and
young females
are
only moderate
to
poor,
especially if they are badly infested
with
warbles.
Therefore
the
fawns
and
young females
will
withstand
very little
food
deprivation
or
harassment without serious consequences.
This
initial
investigation
raises
many questi-
ons:
(1) do range conditions govern
rates
of fertility
in
these
reindeer;
2)
is
twinning
related to the age of the breeding
females
(I
suspect
it
is); and
(3)
do
they really have
a
different and usually
greater
genetic potential
for
growth than
North
American
caribou.
Acknowledgements
The
author wishes to thank
Drs.
G. W. Scotter and
D.
C.
Thomas, Canadian
Wildlire
Service,
tor
encouragement to proceed
w
r
ith
the preparation of this
paper.
Many
thanks
are
extended
to
Betty
Ann
Stanton
for typing and manuscript preparation. The
help
of Dr.
Barbara
Kingscote
for
manuscript
suggestions and review
is
gratefully acknowledged.
References
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150
Rangifer,
Special
Issue
No.
1, 1986
... 4. Which females would probably have ovulated during the following rut (follicle size at time of death). 5. Probably also the minimum number of previous pregnancies (counts of corpora albicantia plus cor¬ pus rubrum, assuming 1) corpora albicantia accessoria were not included among corpora albicantia, and 2) single foetuses, which is usual in Norwegian wild reindeer, but see twin-rates reported by Godkin (1986)). ...
Article
Full-text available
Retrospective reproduction analysis has proven a useful study method for many mammal species, but the method has not been used as much in reindeer and caribou studies as it deserves.
Article
There are hundreds of small reindeer operations scattered across the continental United States. These facilities house small groups of reindeer, typically between 2 and 30 animals. Small ruminant practitioners often are called on to help diagnose and treat a variety of conditions in these reindeer herds. This article discusses the restraint, anesthesia, reproductive management, common diseases, and problems that a veterinarian may encounter when providing care for Rangifer species.
Article
Thesis (Ph. D.)--McGill University, 1963. Includes bibliographical references (leaves 87-99). Photocopy. s
A revision oi the reindeer anc caribou Genus Rangijer-National Museum Ca
  • A W F Banfieid
Banfieid, A. W.F. 1961. A revision oi the reindeer anc caribou Genus Rangijer-National Museum Canada Bulletin 177:1-137.
The development of the foetus of the Norwegian reindeer
  • J Krog
  • M Wika
  • P Savalov
Krog, J., Wika, M. and Savalov, P. 1980. The development of the foetus of the Norwegian reindeer. -In: Reimers, E., Gaare, E., and Skjenneberg, S. eds. Proceedings Second International Reindeer/Caribou Symposium, Røros, Norway, 1979. Direktoratet for vilt og ferskvannsfisk, Trondheim. 306-310.
Reproduction of wild reindeer on the Taimye Peninsula
  • I N Michurin
Michurin, I. N. 1967. Reproduction of wild reindeer on the Taimye Peninsula. -Zoology Journal 46:1837-1841.
Raising reindeer in Alaska. -United States Department Agriculture Miscellaneous Publication No. 207
  • L J Palmer
Palmer, L. J. 1934. Raising reindeer in Alaska. -United States Department Agriculture Miscellaneous Publication No. 207. 40 p.
Land use in the Arctic
  • A E Porsild
Porsild, A. E. 1954. Land use in the Arctic. Part 1. Canadian Geographical Journal 48:232-243. Part 2. -Canadian Geographical Journal 49:20-35.
How Andy Bahr led the great reindeer herd from western Alaska to the Mackenzie Delta
  • G W Scotter
Scotter, G. W. 1978. How Andy Bahr led the great reindeer herd from western Alaska to the Mackenzie Delta. -Canadian Geographical Journal 97:12-19.
Twin fetuses in woodland caribou
  • M W Shoesmith
Shoesmith, M. W. 1976. Twin fetuses in woodland caribou. -Canadian Eield-Naturalist 90:498-499.