Bats

by Debbie Dean

In the distant past, many people thought bats had magical powers, but times have changed. Today, many people believe that bats are rodents, that they cannot see, and that they are more likely than other animals to carry rabies. All of these beliefs are mistaken. Bats are not rodents, are not blind, and are no more likely than dogs and cats to transmit rabies. Bats, in fact, are among the least understood and least appreciated of animals.

Bats are not rodents with wings, contrary to popular belief. Like all rodents, bats are mammals, but they have a skeleton similar to the human skeleton. The bones in bat wings are much like those in arms and the human hand, with a thumb and four fingers. In bats, the bones of the arms and the four fingers of the hands are very long. This bone structure helps support the web of skin that stretches from the body to the ends of the fingers to form wings.

Although bats cannot see colors, they have good vision in both dim and bright light. Since most bats stay in darkness during the day and do their feeding at night, they do not use their vision to maneuver in the dark but use a process called echolocation. This process enables bats to emit sounds from their mouths that bounce off objects and allow them to avoid the objects when flying. They use this system to locate flying insects to feed on as well. Typically, insect-eating bats emerge at dusk and fly to streams or ponds where they feed.

They catch the insects on their wingtip or tail membrane and fling them into their mouths while flying.

There are about 1,000 species of bat, ranging in size from the bumblebee bat, which is about an inch long, to the flying fox, which is sixteen inches long and has a wingspan of five feet. Each type of bat has a specialized diet. For seventy percent of bats, the diet is insects. Other types of bats feed on flowers, pollen, nectar, and fruit or on small animals such as birds, mice, lizards, and frogs.

One species of bat feeds on the blood of large mammals. This is the common vampire bat, which lives only in Latin America and is probably best known for feeding on the blood of cattle. Unfortunately, in an attempt to control vampire bat populations, farmers have unintentionally killed thousands of beneficial fruit-and insect-eating bats as well.

Bats, in fact, perform a number of valuable functions. Their greatest economic value is in eliminating insect pests. Insect- eating bats can catch six hundred mosquitoes in an hour and eat half their body weight in insects every night. In many tropical rain forests, fruit-eating bats are the main means of spreading the seeds of tropical fruits. Nectar-feeding bats pollinate a number of tropical plants. If it were not for bats, we might not have peaches, bananas, mangoes, guavas, figs, or dates.

Today, the survival of many bat species is uncertain. Sixty percent of bats do not survive past infancy. Some are killed by predators such as owls, hawks, snakes and other meat-eating creatures, but most are victims of pesticides and other human intrusions. In Carlsbad Caverns, New Mexico, where there were once eight million bats, there are now a quarter million.

At Eagle Creek, Arizona, the bat population dropped from thirty million to thirty thousand in six years.

Bats often have been burdened with a bad reputation, perhaps because they are not the warm, cuddly sort of animal we love to love. However, their unusual physical features should not lead us to overestimate their harm or to underestimate their value.