84 



Order CHIROPTERA 



Length measurements: head and body about 2 inches (48-52 

 mm.) ; tail \^-2]4, inches (44-54 mm.) ; over-all 354-41/8 

 inches (92-106 mm.) ; hind foot about i/i inch (10-13 mm.) ; ear 

 from notch U^-^'j inches (33-38 mm.). Weight: less than 

 half an ounce (about 12 gm.). 



The skull is of medium size (over-all length about 16 mm., 

 or H inch). Dental formula: I 2/3, C 1/1, Pm 2/3, M 3/3. 



Fig. 58. — Southeastern big-eared bat. 



The large, joined ears and lumps on the nose serve to dis- 

 tinguish this bat from all other kinds in Illinois. Until recently 

 this bat was known by the scientific name Corynorhinus ma- 

 crotis (Le Conte). 



Life History. — Little is known of the southeastern big-eared 

 bat in Illinois. It is known to live in winter and summer in 

 caves or in structures having cave conditions. Individuals live 

 singly or in small colonies; the females when gravid live in 

 colonies separate from those of the males. An adult female usu- 

 ally produces one young in early summer; the young and mother 

 remain together for a period in a nursery colony. Although the 

 big-eared bat appears to be a strong flyer, it apparently does not 

 undertake long migrations and may hibernate in the vicinity, of 

 the summer colonies. The large ears of this bat suggest that 

 they are unusually effective receivers of sound. 



