_Specimens examined_ (4).--2 mi. S, 3-1/4 mi. W Ludlow (Ludlow Cave), 2
(1 SDSU); 10 mi. S, 5 mi. W Reva, 2.
This big-eared bat evidently is uncommon in northwestern South Dakota.
Of the four specimens examined, two were taken at Ludlow Cave and two
were taken in June in the southern part of Slim Buttes--a female shot as
it foraged over a pond in Deer Draw and another female netted over a
water tank at Summit Spring about a half mile south of Deer Draw.
Ludlow Cave, in the caprock on the southeastern edge of the North Cave
Hills, was formed by water erosion, resulting in numerous pockets and
crevises in the ceiling and walls. The cave faces northwest; the mouth
measures approximately 10 feet in diameter. A few feet from the entrance
the cave narrows and approximately 50 feet back it is no more than three
feet in diameter, although in the first 30 feet or so the ceiling varies
from 10 to 15 feet in height. A thorough search of this cave on June 18,
1961, revealed one bat, a male _Plecotus_, which was shot from the
ceiling about 15 feet from the entrance. No bats were found when the
cave was visited on May 16 and again on June 4, 1968. Visher (1914:92)
reported that several _Plecotus_ were found there in early September,
1912. Probably Ludlow Cave, along with the several abandoned coal mines
in the county, serves as a hibernaculum for some species of bats.