The male mentioned above was completely in winter pelage. Adults taken on June 16, 23, and 24 had almost completed molt to summer pelage, but each retained some evidence of active hair replacement, most often over the shoulders; a pregnant female obtained on July 4 had only partially completed the molt to summer pelage. An adult female in summer pelage that was taken on August 4 was inexplicably molting on the sides and over the shoulders.
A May-taken female was parasitized by fleas, Cediopsylla inaequalis (Baker).
Sylvilagus floridanus similis Nelson, 1907
Eastern Cottontail
Specimens examined (2).—4 mi. S, 7 mi. W Ladner, 1; 10 mi. S, 5 mi. W Reva, 1.
This rabbit is uncommon in northwestern South Dakota and evidently is strictly associated with riparian habitats. Our only specimens were taken along the Little Missouri River, where thickets and small cottonwood trees were prevalent, and at the edge of a thicket in spring-fed Deer Draw of the Slim Buttes.
A female obtained on June 26 carried eight embryos that measured 26, and was in process of seasonal molt. Testes of a male shot on May 20 measured 35.
Order Rodentia
Eutamias minimus pallidus (J. A. Allen, 1874)
Least Chipmunk