Sultry Vicky Styles in the 1990 movie, Batman tells the cub reporter that she likes his news coverage and that she likes bats. Hurray. It’s about time that these maligned mammals got some of the respect they deserve, even if it is through the rose‑ tinted lenses of Hollywood.
For centuries folks have associated bats with the mysterious and with evil. People are always threatened by things they cannot see or understand. In Macbeth witches used an eye of newt, a tongue of dog and a wool of bat to make a poisonous concoction. Most people still believe that bats routinely get tangled up in your hair and that all bats are rabid. Thousands of people have been bat‑damaged by the vision of Count Dracula sucking the blood from the necks of young virgins. People that actually like bats are considered to have bats in their belfry.
Bats are not the fluttering mice as the German opera Fledermaus suggests. But the confusion is understandable, bats are mammals yet they fly. An ancient Roman fable illustrates the paradox. “When the birds passed an edict to exile bats from their kingdom, the bats claimed they were mice. The birds then determined that all mice were to be held in contempt. Now the bats protested that they were birds! The animals all became angry and the bats, fearing for their lives, now only come out at night.”
Bats are an ancient group of mammals that have been around for at least the last 65 million years. While there are gliding possums, flying squirrels and soaring lemurs the only mammals that can truly fly are the bats. There are basically two major groups of bats, the insect‑eating and the fruit‑eating bats. The former are more numerous, use echolocation to find prey and are smaller (one is the size of a bumble bee). The latter‑‑also called flying foxes‑‑ find their food visually and are larger (one has a wingspan of six feet).
One in every five mammals is a bat, there are over 950 species found throughout the world. When primitive bats evolved the ability to fly, they were able to exploit a whole new feeding arena by being coming active at night. Birds like swallows and swifts are busy right until sunset, swooping through the air gobbling up flying insects. Then the sun sets and the shift changes. The birds go to sleep and the bats go to work.
The insect‑eating bats are able to see in complete darkness through the use of ultrasonic echolocation. Other animals have also evolved this ability‑‑ some shrews, a few birds, and the dolphins and porpoises. Bats make a number of noises that are audible to humans but most bat sounds are out of our auditory range. High frequency sounds are emitted and focused by the mouth or nose and reflect off the environment. The returning sound waves entering the highly modified ears form a “sound picture” in the bats brain. The image is extremely detailed; bats can distinguish a fine wire .1 mm in diameter, the size of a human hair.
Bats can track down and eat the army of night‑flying insects. In pursuing their prey bats are capable of making sharp and rapid turns. They frequently catch insects not in their mouth but in the skin stretched between the tail and the rear legs. This skin basically acts as a baseball mitt. After catching the insect, the bats toss it into their mouth. Snagging flies for a living. An individual bat may eat as many as 3000 insects in one night. There’s a colony of bats in Texas that eats 250,000 lbs of insects a night. Holy Bat Guano. Most people agree that anything that eats flying insects can’t be all bad.
There are around 15 species of bats in the Bay area. Some remain and hibernate through the winter, others migrate to Mexico and central America. Unfortunately like many other wild animals the number of bats has dropped dramatically in the past 30 years. Some species have already become extinct. But fortunately many people are becoming more aware of the importance of these interesting animals. If you would like more information write to Bat Conservation International, @ Milwaukee Public Museum, Milwaukee, WI 53233.