Endangered Species Handbook

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Persecution and Hunting

Bats

Bats live on every continent except Antarctica and serve extremely important ecological roles as pollinators, seed dispersers and consumers of vast quantities of insects. Although some societies value these useful animals, many persecute all bats, based on irrational prejudice and fears of rabies. The Romanian legend of Dracula, in which a man turns into a blood-thirsty vampire bat at night and flies about seeking victims, has created a ridiculous and false impression. Real vampire bats are small, only about 3 inches in length and weighing about an ounce (Wilson 1997). The three species inhabit neotropical forests and are rare in natural habitat. Only when large numbers of livestock are grazed in an area do these mammals, who suck blood from large animals such as livestock, become common (Wilson 1997). They rarely cause the livestock harm. They are capable of transmitting disease to their host animal, but very rarely do so (Wilson 1997). Bat Conservation International has worked effectively to allay fears about vampire bats and helped many people to see them in the positive light of their value to ecosystems, economies (through pollination), seed dispersal and insect control and their interest as diverse, successful species. But Dr. Merlin Tuttle, founder and Executive Director of the organization, believes that persuading the public that bats are not to be feared is still an uphill battle, in spite of progress made in education programs (Raver 2001). Exaggerated headlines about bats and rabies tend to undo rational education programs. In fact, Dr. Tuttle says that over the past 20 years, the United States has had 1.5 human cases of bat rabies per year, hardly deserving the hysteria that so many people feel at the mere mention of bats (Raver 2001).
One positive change in recent years is the increase in people who rise to the defense of bats when newspaper stories appear about the threats of vampire bats and bat control in buildings (Garvin 1999, Gross 2000). Letters to the editor often make the point that bats are basically beneficial, and articles depicting them as fearsome enemies are misleading and cause persecution of wild bats. One article in The New York Times (Gross 2000) profiled a bat control professional who paid house calls when people complained of bats having entered their homes. He set glue traps, which bats blundered into and then broke their necks, and sent their bodies to a laboratory in the state capital for rabies testing (Gross 2000). Experts have found that only 1 to 4 percent of bats are rabid, and conservationists suggest that bats be set free rather than killed (Gross 2000). A more humane approach to the problem of bats in the attic was developed by Cal Kosky, a wildlife biologist with the Pennsylvania Game Commission. He tapes a piece of plastic or netting over the top of the entrance hole on the outside of the house (Raver 2001). Bats are able to fly out, but are blocked on return. A bat house is placed strategically close to the old hole to provide them with a new home (Raver 2001). Bat Conservation International has an educational video, "Building Homes for Bats," which explains how to construct bat houses to attract bats to backyards where they eat mosquitoes and other insect pests (Raver 2001).* Sensible advice can also be obtained from Dr. Tuttle's 1988 book, America's Neighborhood Bats. Understanding and Learning to Live in Harmony with Them.
Prejudice against bats has had serious consequences for many populations that roost in accessible places, such as open caves. The largest bat colony in the United States, located in Eagle Creek Cave in Arizona, had 30 to 50 million individuals until the 1960s, when vandals and human disturbance reduced them to only 30,000 (Wilson 1997). Several species of North American bats have become endangered as a result of deliberate killing by people, disturbance by spelunkers, and tourists entering the caves (Nowak 1999). The Gray Bat (Myotis grisescens) and the Indiana Bat (Myotis sodalis) of the eastern and Midwestern United States, for example, are both endangered as a result of these activities. Dr. Tuttle has found that the total number of Gray Bats in 22 major summer colonies declined from 1.2 million prior to 1968 to 293,600 in 1976, a loss of 75 percent (Nowak 1999). The Indiana Bat fell from 640,361 in 1960 to 459,876 in 1975; by 1993, 347,890 remained (Nowak 1999). Both species are listed as Endangered by both the 2000 IUCN Red List of Threatened Species and the US Endangered Species Act. In Europe, the Pond Bat (Myotis dasycneme), a related species, has been reduced to only 3,000 in western Europe and fewer than 7,000 in its entire range (Nowak 1999). It is listed as Vulnerable by the IUCN. Many other European myotis bats also have declined to Endangered or Threatened status from habitat loss, disturbance of hibernating colonies in caves and mines, and blocking up of nursery sites in large buildings, such as cathedrals and castles (Nowak 1999). Rather than killing bats that roost in buildings, or blocking up entries, Bat Conservation International encourages the placement of bat houses nearby, which the bats tend to occupy instead. Similar efforts are needed in Europe. Even when allowed to roost in buildings, many bats are poisoned by chemicals used to treat wood in western Europe (Nowak 1999).
Bat caves are often vandalized when bats hibernate in the winter. Vandals enter caves and knock semi-conscious bats to the ground, killing them by the thousands, or even millions. Even entering a hibernation cave can result in mortality because disturbances can arouse them and they use up so much stored energy that they do not survive the winter (Wilson 1997). Many bat caves now have gates that allow bats to fly through the open grating, but keep people out; they have helped protect important bat hibernation areas where bats from large areas congregate (Wilson 1997).
The importance of bats as pollinators is discussed at length in The Natural History of Pollination, by Michael Proctor, Peter Yeo and Andrew Lack (1996). Many types of flowers have evolved to be pollinated by bats, opening only at night. Their internal pollen-carrying structures are designed to drop pollen on the bat's face when it feeds on nectar (Proctor et al. 1996). A great variety of bats and plants coexist, perfectly adapted to one another. Dr. Tuttle's dramatic photos of many such flowers have been published in National Geographic magazine and in the useful book, Bats in Question. The Smithsonian Answer Book (Wilson 1997). He also has made films of bats for nature documentaries. Many bats are extremely attractive, and their sonar is so complex and sensitive that it is only partially understood by scientists. Walker's Mammals of the World, by Ronald Nowak (1999), is another important source of information on bat biology, taxonomy, behavior, conservation and related subjects.
After rodents, bats have the greatest number of species of any mammals, with the most diversity in tropical areas. The number of threatened species has increased dramatically over the past decade as a result of persecution, killing for food, pesticides and other toxic chemicals, and loss of their habitat (see Appendix for list of threatened species). The majority of species at risk suffers from a combination of these factors.
*This video can be ordered online at www.batcon.org or by calling 1-800-538-BATS.


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