There was no sign that adult female No. 11 whelped or attempted to
locate or construct a den. The usual gestation period for wolves is
about 63 days (Brown 1936). Because No. 11 was seen coupled in
copulation on February 12 and 16, she should have whelped between April
13 and April 21, if she had conceived. Probably she would have moved
little during the preceding 2 or 3 weeks (Mech 1970). However no such
changes in this animal's movements were noticed. The three wolves stayed
near Kenton between April 15 and April 18 but also killed a deer during
that time. They moved extensively from April 19 to May 7. The only
indirect evidence that the female may have been pregnant was an
observation made by a local citizen on April 5 (Table 6) who saw the
three wolves and stated that the small wolf looked "fat." This would
probably have been No. 11, but a full stomach could easily have been
mistaken for pregnancy.
Unfortunately, neither the reproductive tract collected from No. 11 in
September nor the blood sample taken in early March shed any light on
the cause for the wolf's failure to produce pups. The ovaries did
contain _corpora albicantia_, indicating that at some time the wolf had
ovulated, but it could not be stated with certainty just when (R. D.
Barnes, personal communication). The blood progesterone levels were more
helpful. No. 11 had 3,560 picograms of progesterone per milliliter,
compared to 56 picograms per milliliter for Wolf No. 10, whose
reproductive tract appeared immature. This high progesterone level of
No. 11 indicated that the animal had recently ovulated, but it was
impossible to tell whether she was carrying any fetuses at the time the
sample was taken (U. S. Seal, personal communication).