Missouri Bats

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Published on: Mar. 2, 2000

Last revision: Nov. 4, 2010

Bat Counts

seed dispersal for some species, and nectar-feeding bats are responsible for the pollination of many species of plants. In fact, more than 400 products used by humans come from bat-pollinated plants. These products include bananas, avocados, cashews, balsa wood and tequila.

Missouri bats help control nocturnal insects, some of which are agricultural pests or, in the case of mosquitoes, annoying to people. Many forms of cave life depend on the nutrients brought in by bats and contained in their guano.

Bat Myths

Bats have been the subject of folklore and superstitions for thousands of years. Their habit of sleeping in caves and flying at night have helped to promote myths about bats. Those stories leave us with the impression that bats are nasty and filthy animals that possess the supernatural power of shifting shape from bat to man. Movies in which bats turn into blood-sucking vampires have increased people's fear of bats.

Such misinformation has resulted in needless and senseless persecution of bats. The beliefs that bats are blind or that they will fly into your hair are simply not true. Bats see quite well; they just don't see colors. They are also able to detect and avoid objects as fine as a single human hair.Bats are commonly feared because they can carry rabies. Although rabies is a serious disease, it occurs in only a small percentage of bats (less than 1/2 of 1 percent). Bats that contract the disease die quickly and rarely show the aggressiveness shown by rabid dogs and cats. As with any wild animal, if a bat allows you to approach it, the animal is probably sick and should be avoided.

Endangered Bats

Worldwide, many bat populations are declining at an alarming rate. Special methods of protection have been established to help protect these dwindling populations. Two Missouri cave bat species, the gray bat and the Indiana bat, are listed as federally endangered by the U.S. Fish and Wildlife Service and state endangered in Missouri.

Ozark big-eared bats (Corynorhinus townsendii ozarkensis), which used to live in caves in southwestern Missouri, have not been observed in Missouri since 1971. This species, also state and federally listed as endangered, lives only in a few caves in northwestern Arkansas and northeastern Oklahoma. The Ozark big-eared bat was listed as endangered because of its small population, reduced distribution and vulnerability to human disturbance. Habitat loss and disturbance at maternity caves and hibernation sites are likely causes of its decline.

Conservationists are taking protective management measures to assist in the protection of these species. These include gating or fencing important bat caves and placing warning or interpretive signs at other caves to minimize human disturbance.

BAT BIOLOGISTS

To avoid disturbing bats unnecessarily, the Conservation Department allows just two biologists to census hibernating gray and Indiana bats, and then only on a two-year cycle.

Every winter biologist Rick Clawson (top) takes precise temperature readings of the air near the bats and the bedrock to which they attach. They count small clusters individually, and measure larger ones, multiplying them by a known bat-density factor--about 170 per square foot for grays, and 400-500 for Indianas. Only 44 hibernacula are known for these bats in Missouri, but others may remain undiscovered.

In summer, gray bats occupy about 64 maternity caves, where larger rooms and warm conditions are suitable for bearing young. Entering a maternity colony is harmful to the bats, so Conservation Department researchers (from left) Clawson, Norman Murray & Brian Loges visit some of the sites in the fall, after the bats have left, to measure the area of fresh guano (center), which is distinguished by a darker color, presence of fungi and other characteristics.

Recently, Conservation Department bat biologist Bill Elliott placed electronic temperature dataloggers in bat caves to record the temperature variation at bat roosts.

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