• Bats may be the least appreciated animals occurring in the Eastern United States, although as consumers of enormous numbers of insects, they rank among the most beneficial.
• Many people incorrectly believe that bats are blind, try to become entangled in human hair, are dirty and dangerous, and otherwise do things that drive people “Batty” or cause them to have “bats in their belfries”. Being referred to as an “old bat” or a “dingbat” is less than complimentary. Actually, most bats are highly beneficial, intelligent, extremely interesting, and possess fascinating abilities, such as homing instinct and the ability to navigate by echolocation in complete darkness.
• Bats, like humans are mammals, having hair and giving birth to living young and feeding them on milk from mammary glands. More than 900 species of bats occur worldwide; they are most abundant in the tropics. Bats are second only to rodents in numbers of species, and compromise almost 25% of all species of mammals. Forty-four species of bats are native to the United States, and 19 of these species occur in the eastern United States.
• Worldwide, bats vary in size from only slightly more than 2 grams (about the weight of a dime) to about 1,500 grams (more than 3 pounds). The large “flying foxes” of Africa, Asia, and Australia, and many Pacific Islands have a wingspan of up to 2 meters (6 feet).
• Bats of the eastern United States vary in size from fewer than 3 grams in the eastern small-footed bat to nearly 50 grams in the Wagner’s mastiff bat. The largest bat in the eastern United States, Wagner’s mastiff bat, which occurs in southern Florida, has a wingspan of 50 centimeters (20 inches).
• Bats are the only true flying mammals and their maneuverability while capturing insects on the wing is astonishing. Bats belong to the mammalian order Chiroptera, which means “hand-wing”.
• The bones present in a bat’s wing are the same as those of the human arm or hand, but finger bones of bats are greatly elongated and connected by a double membrane of skin to form a wing.
• The oldest known fossil bats, from Wyoming and Europe, date back about 50 million years.
• Bats primarily are nocturnal, although many can be seen flying about in the early evening, sometimes even before sunset. Occasionally, especially on warm winter days, they can be observed flying in daylight hours.
• Bats have good eyesight, but most depend on their superbly developed echolocation system to navigate and capture insects in the dark. Bats emit pulses of high- frequency sound (most are not audible to human ears). By listening to the echoes reflected back to them, bats can discern objects in their path. So acute is their ability to echolocate that they are able to avoid obstacles no wider than a piece of thread and capture tiny flying insects, even in complete darkness.
• All bats in the eastern United States feed almost exclusively on insects and thus are extremely beneficial. In fact, bats are the only major predators of night-flying insects. A bat may eat more than 50% of its own body weight in insects each night (approximately 3,000 or more insects).
• Bats, like many other mammals, can contract and transmit rabies as well as other diseases. Although rabies has been found at one time or another in most species of bats in the United States, it is relatively uncommon. Rabid bats seldom are aggressive. Fewer than 40 people in the United States are known to have contracted rabies from bats in the past 40 years; in fact, rabies was not known to occur in bats until the 1950’s. Far more people are killed by dog attacks, bee stings, power mowers, or lightening than rabies. However, because bats can carry and transmit rabies, they should not be handled. This is especially true for bats found on the ground, because they may be unhealthy.
• Some bats may take up residence in houses or other places where they are not wanted. Usually, the best method of preventing bats from roosting in houses or other buildings simply is to install one- way valves over the openings through which they enter. Alternatively, these openings can be closed, but this should be done during the time of year when bats are not present (usually September through March) or at night after bats leave to forage for insects. Care must also be taken not to trap flightless young bats in buildings.
• As people discover bats are beneficial and not dangerous, more and more attempt to attract bats, much in the way they can attract certain songbirds. Many people have placed bat houses in their yards to take advantage of the insect-eating habits of bats. Information on bat houses and other bat related items can be obtained from Bat Conservation International, P.O. Box 162603, Austin, TX 78716-2603.
• Dramatic reductions in populations of bats have occurred in recent years in the United States and worldwide. Although owls, hawks, raccoons, skunks, and snakes occasionally may prey on bats, few animals consume bats as a regular part of their diet. Humans seem to be the only animal having a significant impact on the populations of bats. Adverse impacts by humans include destruction of habitat, direct killing, vandalism, disturbance of maternity and hibernating colonies, and use of pesticides (on their food- insects) and other chemical toxicants.

People can help preserve our beneficial bats by following some common sense guidelines.

Disturbance of hibernation and maternity colonies by humans is a major factor in the decline of many bat species. Even well-meaning individuals, such as cave explorers and biologists cause these disturbances. Hibernating bats arouse from hibernation when disturbed by people entering their caves. When aroused, they use up precious winter fat stores needed to support them until insects become available in spring. One arousal probably costs a bat as much energy as it normally would expend in 2-3 weeks of hibernation. Thus, if aroused often, hibernating bats may starve to death before spring. Disturbance to summer colonies is also detrimental. Maternity colonies cannot tolerate disturbance, especially when flightless young are present. Baby bats may be dropped to their deaths or abandoned by panicked parents if disturbance occurs during this period.

© 2005 Tennessee Bat Working Group / Tennessee Wildlife Resources Agency, All Rights Reserved.