Bats are mammals. They have fur, produce live, undeveloped young, and nurse with pectoral breasts. They are the only flying mammal. Bats are not rodents; they are most closely related to lemurs. They both share a common ancestor with primates.
Fossils prove that bats have been inhabitants of our planet for over 50 million years; fossilized remains of these ancient bats closely resemble the bones of our present day bats.
There are nearly 1100 species of bats worldwide (1/4 of all mammal species). The smallest is the Bumblebee Bat of Thailand, weighing less than a penny. The largest bat is the Flying Fox of Indonesia, with a wingspan of nearly 6 feet. 45 species are found in the US and Canada.
Bats use echolocation for navigation and hunting. Bats are not blind; many have excellent vision. They use echolocation because they are most active at night.
In temperate areas, bats will migrate 300 miles, or more, to a suitable hibernation site. Some bats even travel from Canada to the Gulf of Mexico. Bats are very loyal to their birth and hibernation areas.
Bats that live in this area mate in the fall before hibernation. Sperm is stored internally throughout the winter; in the spring, when warmth and food bring them out of hibernation, fertilization is triggered. Gestation lasts 6-8 weeks. Pregnant females form nurseries; males and non-breeding females form dormitories. Bats are the slowest mammal reproducer, giving birth to only one young (perhaps 2 in some species and 4 to 5 in our foliage roosting species) per year. But they are exceptionally long-lived, some with a life span of more than 34 years.
Many bats live in caves, while some live in hollow trees or under bark. Some, such as flying foxes, inhabit large roosts in trees. 70% of bat species eat insects. 25% eat fruit or nectar (tropics). The remainder eat meat, fish, or blood.
Little Brown Bats may eat 1200 mosquitoes in an hour. A colony of 50 Big Brown Bats can protect the farmer by eating up to 11 million root worm moths in a summer.
Insects are repelled by the existence of bat colonies. They retreat when bats are heard.
There are 12 species of bats found in Indiana, 9 inhabit the northeastern part of the state:
- Little Brown Bat - common
- Big Brown Bat - common
- Eastern Red Bat - common
- Tri colored Bat - common
- Northern Myotis - common
- Silver-haired Bat - uncommon
- Hoary Bat - uncommon
- Evening Bat - uncommon
- Indiana Bat - rare