In Illinois, most bats mate in autumn before enter- 

 ing hibernation or during migration. The females don't 

 become pregnant, however, until hibernation ceaseS in 

 the spring. In this reproductive pattern, known as de- 

 layed fertilization, sperm remain viable and are 

 nourished by specialized cells in the female's reproduc- 

 tive tract until ovulation and fertilization occur. 



their own — about 21 to 30 days after birth. 



Like many other animals, bats worldwide are 

 seriously threatened by human activities. The worst 

 threats to bats are loss of habitat, disturbance by hu- 

 mans, and poisoning from pesticides. Fortunately, all 

 bats in Illinois are protected by law, but the Indiana 

 bat, the gray bat, the southeastern hat, and Rafines- 



Hoary bat 



. ,_ c Merlin Tultle. The National Audubon 

 .♦# Sociely Colleclion PR 



Young bats, called pups, are generally born be- 

 tween late May and early June. Depending upon the 

 species, bats may have a single pup or up to five in a 

 litter. Females are very attentive mothers, grooming 

 8 and nursing their pups until they can fly and forage on 



que's big-eared bat are classified as state endangered 

 species by the Illinois Endangered Species Protection 

 Board. The Indiana bat and the gray bat are also listed 

 as federally endangered species by the U.S. Fish and 

 Wildlife Service. The Illinois Natural History Survey, 



