_Specimens examined_ (31).--2 mi. N, 5 mi. W Ludlow, 15; NW 1/4 sec. 15,
R. 5 E, T. 22 N, 2; 2 mi. S, 3-1/4 mi. W Ludlow, 2; NW 1/4 sec. 32, R. 1
E, T. 20 N, 1; 9 mi. S, 7 mi. W Reva, 1; 10 mi. S, 5 mi. W Reva, 9; NE
1/4 sec. 8, R. 8 E, T. 16 N, 1.
The least chipmunk is common in the buttes and associated badlands
where it most frequently inhabits rocky areas. Visher (1914:88) reported
_E. minimus_ from Harding County ("abundant in badlands"), but his paper
has been overlooked by most subsequent workers. Visher's mention of a
chipmunk from the mouth of the Moreau River in north-central South
Dakota, incidentally, would seem to be in error, as would the report by
Over and Churchill (1945:28) of _Eutamias_ inhabiting "... thickets
along the Little Missouri River of Harding County."
Females evidently bear but one litter annually (in late May) in
northwestern South Dakota and young are weaned by the latter part of
June. Females taken on May 15 and 19 carried embryos (five measuring 30
and three measuring 28, respectively). A lactating female with five
placental scars was obtained on May 24, but eight adult females taken
after June 23 previously had weaned young. Juveniles were collected on
June 24 and 25. Testes of two adult males collected in mid-May measured
11 and 18, but males taken in summer had much smaller testes.
In late spring, most adult least chipmunks molt from the worn, drab-gray
pelage of winter to a brighter, more tawny summer pelage, but molt in a
few females, perhaps originally delayed by reproductive activity,
continues well into the summer months. Of seven specimens taken between
May 15 and 24, two (one male and one lactating female) were in an early
stage of molt, whereas the remainder were in winter pelage. Nine
specimens (four females and five males) taken in mid- and late June were
molting, but two females collected then were in winter pelage, and three
animals, two males and a female, had completed molt to summer pelage.
One adult female taken on August 5 had yet to complete molt to summer
pelage. In our material, the first indication of molt from winter to
summer pelage appears on the top of the head and the cheeks. Thereafter,
molt proceeds posteriorly over the shoulder region and more or less
evenly along the back and sides. In two specimens, small patches of molt
preceded the general molt line. Molt on the venter apparently begins
after molt on the dorsum approaches completion, but we could discern no
definite pattern; on four specimens, hair was being replaced on the
venter in scattered patches.
An August-taken young of the year engaged in post-juvenal molt had new
adult pelage in a vague hour-glass pattern in the dorsal trunk region as
well as on the cheeks and anterior part of the head. It was actively
molting on top of the head, between the ears, over the shoulders,
laterally behind the front feet, and along the sides, and had old pelage
on the rump. Ventrally, the new adult pelage was evident only along the
midline.
One adult male examined for ectoparasites harbored a tick, _Dermacentor
andersoni_ Stiles, and fleas, _Monopsyllus eumolpi_ Rothschild.
~Spermophilus tridecemlineatus pallidus~ J. A. Allen, 1874