BATS 55 



periods of unfavorable weather some species of bats go into dormancy, a 

 condition of reduced animation resembling that of hibernating chipmunks. 

 But we learned nothing in this regard concerning the bats of the Yosemite. 



The young of the Little California Bat are born during the early 

 summer months. A female taken at Pleasant Valley May 21, 1915, con- 

 tained one large embryo ; and in a group of these bats secured on July 13, 

 1920, there were five females each accompanied by a single youngster one- 

 third to two-thirds grown. With this bat, young are borne but once each 

 year, and there is only one young at a birth. These facts indicate that 

 the existence of the species is relatively a very safe one — assuming of course 

 that the birth rate has been adjusted to the maximum 'expectation' of 

 casualty. 



On July 13, 1920, an examination of the deserted, windowless buildings 

 at the McLaughlin mine south of Dudley revealed the presence of eleven 

 Little California Bats. Those mentioned in the preceding paragraph 

 were of this lot. These bats were found by systematically ripping off the 

 muslin-mounted wall paper. They were on the west side of the building 

 where the wall was shaded on the outside by trees. Much previous pound- 

 ing on the walls of other parts of the building had not disturbed them 

 in the least. The bats were not clustered together, as is typical of colonial 

 species, but were clinging individually to the rough boards beneath the 

 loosened wall paper, within a circle 2 feet in diameter and only about 30 

 inches from the floor. There were five adult females (all in nursing 

 condition) and five young (three females and two males). The young were 

 clinging to the walls independent of, but close to, their mothers. Off to 

 one side was a female without any young one. Later, when confined 

 together in a box, two of the adults were found each with a young one 

 attached to a nipple. The young ranged in weight from 1.6 to 3.0 grams, 

 while the weight of the adult females averaged 4.3 grams. 



High Sierra Bat. Myotis lucifugus altipetens H. W. Grinnell 



Field characters. — Size medium (larger than Little California Bat, smaller than 

 Large Brown Bat). (See pi. 21e.) Total length 3% inches (91-93 mm.) ; lower leg 

 (tibia) well under % inch (15.3-16.4 mm.); hind foot % inch (10-11 mm.); ear % 

 inch or over (13-15 mm.). Coloration light brown above, buflfy beneath. Distinguished 

 in hand by relatively large hind foot, more than half length of tibia. 



Occurrence. — Inhabits Canadian and Hudsonian zones on Sierra Nevada. Altitudes, 

 7500 to 10,350 feet. Recorded at Merced Lake and Vogelsang Lake. Flies over and 

 about tops of forest trees, and over lakes. 



Bats inhabit the entire extent of the forested regions of the Sierra 

 Nevada but each species occurring there occupies a definite part of this 

 general range. The territory of the present species involves two high 



