The eastern pipistrelle (Pipistrellus subflavus) can be found all over the eastern half of the United States from Canada down to Central America.
Bats are an incredibly diverse and ecologically beneficial group of animals. Worldwide there are nearly 1,000 bat species representing almost a quarter of all mammal species. They are the second largest order of mammals in number of species (second only to rodents), and can occupy virtually every habitat worldwide except in the most extreme desert and polar regions. There are forty-five bat species native to the United States. Nearly 40 percent of these species are threatened or endangered, and around the world, many more are declining at alarming rates. Six U.S. species are listed as endangered and 20 are considered species of special concern by the U.S. Fish and Wildlife Service. Declines have been primarily attributed in the past to human impacts such as habitat destruction, direct killing, disturbance of hibernating and maternity colonies, cave vandalism and use of pesticides and other chemical toxins. Negative human perceptions of bats can have a huge detrimental effect on their conservation. More recently, declines have been primarily attributed to a disease called white-nose syndrome. This disease was first discovered in January 2007 and has caused huge bat mortalities among hibernating cave-dwelling bats. Extensive research is currently being done to try and determine causes and possible cures for this disease.
Big brown bats (Eptesicus fuscus) provide the ecological benefit of consuming large quantities of agricultural pests.
Unfortunately, there are a lot of misconceptions surrounding bats and bat behavior that have given this group of animals an undeserving negative reputation. One common misconception regarding bat behavior is that they are hostile or aggressive animals. Bats are not aggressive and in general, will do their best to avoid people. People are much more of a threat to bats than bats are to people. Another common misconception is that all bats carry rabies and other diseases. In actuality, less than 0.5 percent of bats have rabies. The chance of contracting rabies from bats is even further diminished if you simply never pick one up. Although the likelihood of contracting rabies from bats is very small, because rabies is a serious and fatal disease you should never pick up a bat, and you should contact your local health department if you have been bitten by a bat.
Bats are actually very beneficial. Most bats are insectivores and therefore provide the ecological benefit of acting as a natural pest control. An individual little brown bat or gray bat, for example, can consume over 1,000 mosquitoes in one hour. With increased fatalities occurring from West Nile virus, bats can be thought of as a natural source for controlling mosquito populations and therefore reducing occurrences of the virus. Bats also help to control agricultural pests. Big brown bats, for example, are predators of several agricultural pests such as June bugs, moths and beetles. Mexican free-tailed bats consume huge quantities of the corn earworm moth, which causes over $1 billion in crop damage a year.* Many farmers in the U.S. have installed bat houses on their farms to try and encourage the growth of bat populations. Large bat colonies on farms can greatly reduce insect populations and therefore reduce the need for pesticides.
Bat houses can aid in the conservation of bats by providing artificial roosts for bats whose natural habitat is declining. Hundreds to thousands of bats can occupy a single bat house. These relatively cheap houses have been found to be very successful in providing shelter for many bat species and reducing insect abundance in the immediate area. If you are interested in controlling insect populations on your property and aiding in the conservation of bats, you might consider putting up a bat house.
Left: Rafinesque’s big-eared bat (Corynorhinus rafinesquii) is a rare bat species found in the Southeastern United States. Right: Bat houses have been found to be very successful in providing shelter for many bat species and reducing insect abundance in the immediate area.
Besides being beneficial as a natural pest control, bats in the western U.S. also provide the ecological benefit of pollinating many plants. The agave plant, for example, which is used to produce tequila, is pollinated by bats. Other plants that rely on bats for pollination include bananas, peaches and cashews. There are many species of fruit bats or flying foxes in other countries that solely eat fruit and provide the benefit of seed dispersal. Through their droppings they will disperse seeds and have been known to reforest entire areas. Fruit-eating bats have played a major role in regenerating rainforests in areas that have been cleared.*
If you would like to learn more about bats or become involved in bat conservation, visit the Bat Conservation International website to find out more: www.batcon.org.
*editor's note: The range of these bat species is limited within the US. Research bats in your area before trying to attract a specific species.
A version of this article appeared in a February 2011 print edition of State-by-State Gardening.
Photography courtesy of istockphoto.com/jollyphoto and AlisonMcCartney.