The Bats

Mention bats and most people shudder, apparently convinced they're ugly, creepy, even vicious creatures, somehow associated with evil. But are they? Or have they just gotten a lot of bad press over the years?

Few of us have actually seen bats close up, and fewer yet know anything about them, except what we may recall from horror movies and sensationalized stories in the media.

The truth is that bats are gentle, intelligent, and beneficial to mankind. They're about as evil as puppy dogs.

Researcher Yar Petryszyn of the University of Arizona has worked with bats for many years. "They're actually very cute little animals," he says, "and their adaptationto their unusual life-style is fascinating."

Dr. Petryszyn often lectures to grade school students and conservationists. When he does, he takes a live bat with him.

"The audience loves it," says Petryszyn enthusiastically. "Once people see the bat's appealing face and have the chance to pet its soft, fluffy fur, they're delighted. The old stereotyped impressions fly out the window, and most folks become very concerned about the plight of bats.

Two Arizona bats that certainly fit the "appealing" category are the Sanborn's and Mexican long-tongued bats. Both have small dog-like faces, big eyes, and gentle dispositions. They feed on nectar and pollen and act more like hummingbirds than bats. In fact, they are the major pollinators of saguaro and organ-pipe cactus as well as certain agaves, such as century plants.

The nectar feeders are tropical animals and migrate from Mexico, arriving in southern Arizona in early May, just as the saguaro flowers begin blooming.

"Nectar-feeding bats are specially equipped to pollinate flowers," explains Donna Howell, a bat researcher and consulting biologist. "They have an extremely long tongue, which has a brush of bristles at the tip that mops up nectar as the bat hovers at a blossom."

As the bat pushes its snout into a flower to lap up nectar, its head, neck, and chest are dusted with pollen, which is then transferred to the next flower it visits. Saguaro, organ-pipe, and century plants produce copious amounts of nectar, says Dr. Howell; and the bats, which have prodigious appetites, feed until they can't hold another drop, then retire to a night roost to rest, digest, and groom. Later they'll fly off for another bout of feeding.

The Arizona Nature Conservancy's MileHi Preserve in Ramsey Canyon in the Huachuca Mountains, long famous for its hummingbirds, is becoming known for its bats as well. Several years ago, hummingbird feeders in the canyon began mysteriously turning up empty each morning. The puzzled staff kept watch one night and discovered that the thieves were nectar-loving bats that had learned to drink from the feeders!

"The only problem is that the bats, with their long tongues, tend to be sloppy when they drink, and the feeders get very sticky," report Tom and Debbie Collazo, managers at Mile-Hi. "But once guests learn of the bats, they often are fascinated by them. Many now make reservations especially to see the bats."

Another bat that helps dispel the ugliness rumor is the spotted bat. This beautiful creature's pale pink wings and ears form a sharp contrast to its silky black fur which is splotched with white spots. The most striking feature, though, is the size of those enormous pink ears-the largest of any North American bat, more than half the length of its body. The spotted bat holds its huge ears erect only when it's awake and Gentle, intelligent, beneficial, fascinating — even cute. But the years of bad press are killing them alert. When sleeping, it folds them up to conserve body heat. This stunning bat is so rare most researchers have never seen one in the wild, and little is known of its habits.

The Bats

The nectar feeders and the spotted bat are only a few examples of the more than two dozen species that inhabit Arizona. The reason this state is so favored is its wide variety of habitats. Canyons, caves, old mine shafts, jumbles of boulders, and crevices in cliff walls all serve as roosting and hibernating sites.

Water is another important factor in attracting bats. Most bats usually fly out to a pond, lake, or river first thing in the evening. They drink on the wing, skimming low over the water and gulping a mouthful at a time. In areas where water is scarce, bats may fly many miles to find a water hole or stock tank. (A conservation-minded rancher near Portal regularly checks his tanks for bats that may have fallen in. He fishes them out, dries them off, and releases them, reporting any unusual finds to bat researchers at the U of A. Recently he discovered a brown bat banded 20 years earlier at the Southwestern Research Station near Portal!) Even though there are literally millions of bats in Arizona, they are still creatures of mystery surrounded by superstition. They are nocturnal animals, and usually live in remote caves, so that we seldom see them. Their unusual trait of hanging upside down also makes them seem strange to us. Though their habits may seem peculiar, they show how well bats are adapted to function and environment.

Hanging upside down, for instance, makes perfect sense to a bat. Donna Howell and other researchers believe it came about as an adaptation to flight. "Flying animals must be as lightweight as possible," she says. Many Arizona bats weigh less than an ounce. Bats have evolved in various ways that have limited their weight, such as developing light membranous wings and thin leg bones. A glance at a bat reveals a powerful and muscular chest but a tiny pelvis and skinny legs. The leg bones are so thin, in fact, that they cannot support the bat's weight in an upright position. When the bat hangs upside down, its weight is suspended, enabling the bones to support a much greater load. Hanging upside down also allows the bat to simply fall into flight, a very energy-efficient way to launch. Arizona's largest bat, the Western mastiff with a wingspan of nearly 2 feet, has to roost where it can fall 10 to 20 feet.

Living in caves also makes good sense to these creatures. In fact, caves provide perfect homes for most bats. In such dark, quiet, secluded places, bats can spend the day sleeping, secure from predators. Hanging from the ceiling makes them even less accessible. Equally important, bats are very temperature-sensitive and require precise and stable combinations of temperature and humidity. Admittedly, few caves meet such exact conditions, so the bats move about, using certain caves in summer for breeding, others in winter for hiberating.

But not all bats live in caves or mine shafts. Arizona also claims several of the more solitary tree-dwelling species such as the red, hoary, silver-haired, and yellow bats. These usually roost alone, hanging amidst the foliage of cottonwoods, willows, sycamores, and palms. They also tend to be fairly hardy, able to tolerate greater variations in temperature than their cave-dwelling cousins.

The hoary bat has fur on its feet, ears, and underwings, enabling it to survive at higher elevations and in colder conditions. This handsome bat can even be found roosting in pine trees.

The colorful pelage of the red bat might seem to make it more noticeable, yet this fellow may easily be overlooked as he hangs by one foot in a sycamore or mimics a dead leaf or a piece of ripe fruit in the branches of a peach tree.

The silver-haired bat also roosts in trees but tends to hide under old loose bark on the trunk. The yellow bat prefers to hang among the dead fronds of palms. Still other species such as the pallid, the Western pip-istrelle, and the Western mastiff wedge themselves into cracks and niches in cliff walls to roost.

The delicate pipistrelles, though among the most common bats of the desert, usually roost singly or in very small groups. The tiniest bat in North America, the pipistrelle is no larger than a beetle and weighs about as much as a nickel. This is probably the most commonly seen bat, since it's the first one out in the evening, often before dusk.

By contrast, the pallid bats, cream-colored creatures with large pink ears and big eyes, seem a rowdy group. As many as a hundred will stuff themselves into one small crevice where they can sometimes be heard noisily squabbling among themselves.

Bats fulfill an ecological role very similar to that of insect-eating birds. The difference is that, by hunting at night when birds and other predators are asleep, the bats have a huge supply of insects all to themselves. To get their choice of insect morsels, the various bat species employ different foraging strategies; some hunt high above the treetops; others, like the leaf-nose bats, hover around foliage, snatching caterpillars, moths, beetles, and cicadas; while pallid bats capture their prey on the ground, dining on grasshoppers, crickets, and scorpions.

Because of their high metabolic rate, bats feed voraciously, eating a quarter to half their body weight in insects in a night. As a matter of fact, one Arizona colony of Mexican free-tailed bats was found to devour about 350,000 pounds of insects, or about the equivalent weight of 34 ele-phants, every night!

But beneficial as they are, most bat populations have fallen on hard times. Loss of habitat and widespread use of chemical pesticides such as DDT have caused a dramatic decline in bat numbers. Arizona's largest Mexican free-tail colony mentioned above, for example, was 30 million strong in 1963; six years later, it numbered just 30,000 individuals. And even the nectar-feeding Sanborn's bat now is being considered for inclusion on the federal threatened or endangered species list. Colossal Cave near Tucson once had one of the largest populations of these bats. Today it has none.

The general public's prejudice and misunderstanding are other factors responsible for many bat deaths. Fear of disease, especially rabies, is perhaps the principal reason people kill bats.

Although it's commonly believed that most bats are rabid, Dr. Petryszyn points out that in Arizona the disease appears to be limited to only 2 of our 28 species. Furthermore, the State Health Department reports that there has never been a recorded case of bat-transmitted rabies in Arizona, and in the entire United States and Canada there have been only 12 cases in the last 40 years. Dr. Merlin Tuttle, president of Bat Conservation International, declares: "The fear of bat rabies is totally out of proportion to the actual threat. More people die annually from bee stings or pet dog attacks." But as with all wild animals, bats should not be handled or touched, and any bat found lying on the ground should be considered sick.

With their poor public image, bats need all the help they can get. "The single most critical conservation need of bats today is increased public awareness and education," says Dr. Tuttle. He believes the image of the lowly bat can be changed to that of a valuable and intriguing animal, an essential part of our natural heritage and worthy of protection.

And certainly it is that. According to Dr. Don Wilson, chief of the U.S. Fish and Wildlife Service's Biological Survey, "Losing even just the nectar-feeding bats could have serious consequences in Arizona. The plants that depend on bats to pollinate them would decline, and animals dependent on those plants would also be affected. That in turn would impact on others, right down the line. You can't change one part of the system without affecting all the other parts as well."

So will we humans determine to save the bats? Certainly not until we put to rest the negative associations and superstitious fears that made us scorn them in the first place.

How long will that take? Who knows? But let us hope it is soon. For the bats' sake, and for our own.

Selected Reading

Bats of America, by Roger W. Barbour and Wayne H. Davis. University Press of Kentucky, Lexington, 1969.

The Lives of Bats, by D.W. Yalden and P.A. Morris. Quadrangle/The New York Times Book Co., New York, 1975.

Bats: A Natural History, by John E. Hill and James D. Smith. British Museum (Natural History), London, England, 1984.