_Specimens examined_ (22).--2 mi. N, 5 mi. W Ludlow, 5; 19 mi. N, 1 mi.
E Camp Crook, 2; 2 mi. S, 2 mi. W Ladner, 1; 6-1/2 mi. N, 2 mi. W Camp
Crook, 1; 1/2 mi. W Reva, 3; 4 mi. S, 1/2 mi. W Reva, 1; 6 mi. W Reva,
7; 15 mi. S, 4 mi. W Reva, 1; 7 mi. S, 4-1/2 mi. E Harding, 1.
Ground squirrels are common in areas of short grass; we observed them
most frequently along roadways and fencerows in otherwise overgrazed
flats. Many of our specimens were shot or taken in break-back traps
baited with rolled oats in just such situations.
Young from the first litters of the year were above ground by late June
and represented the largest segment of the population at that time; for
example, only three of 17 individuals collected from June 20 to 27 were
adults. Adult females collected on June 20 and July 7 had enlarged
mammae but were no longer lactating.
Time of emergence from hibernation in northwestern South Dakota is
unknown, but many ground squirrels were active in the last week of
March, 1963. A male obtained on March 28 had testes that measured 27 and
was in full winter pelage, which is easily distinguished from the
shorter, darker pelage of summer.
~Cynomys ludovicianus ludovicianus~ (Ord, 1815)