Myth: Bats are rotten little creatures and people should avoid them at all costs.

Fact: The bat is your friend.

"What?" you cry in horror. Those nasty little creatures of the night that hang upside down in people's attics, suck the blood of little children, fly into women's hair and carry rabies to boot?

"We've been working on trying to improve the bat's public image since 1974, when there were three species on the endangered list today there are five ," says Phoebe Wray, who calls herself a "bat advocate" and heads the Center for Action on Endangered Species in Ayer, Mass.

"At first we were just working on the endangered ones, but we soon found that we had to battle the whole problem of a public image based on centuries of bad press."

The average person's fear of bats is "absolutely unwarranted," claims Guy Hodge, a naturalist who works for The Humane Society of the United States and leads evening "bat walks" for children and adults in his Fairfax County neighborhood.

"Bats are unique in that they are the only mammals that can truly fly. But most of what we fear about them--that they attack people and carry rabies--just isn't true." (The vast majority, by the way, eat only insects or fruit, and the only vampire bats in the U.S. are in zoos.)

Wray speculates that the "bad press" associated with bats began during the Middle Ages, when medieval artists began putting bat-like wings on their demons.

"Bats are creatures of the night," she notes, "and in the West we associate the night with evil things." In eastern countries, she points out, bats are considered good luck, and they appear frequently in Egyptian cave paintings.

Although Hodge and Wray maintain that the bat's bad rep is undeserved and based mostly on a lack of human understanding, they concede they're not exactly the kind of animal you'd like to hold in your lap. "Even as babies," says Hodge, "they're not what you'd call cuddlesome."

Whether you like them or not, bats are, evolutionarily speaking, a successful bunch. Bat fossils date back some 50 million years. Scientists speculate that they evolved from insect-eating shrews to exploit a previously uninhabited ecological niche: the nearly unlimited supply of night-flying insects unchased by the daylight-flying birds. Today there are nearly 1,000 different species of bat, and they live everywhere except where it's extremely cold. In this area, most of the bats are either Big or Little Brown bats; they eat insects, not people or pets.

Bats also live to be old. Because they are mammals and don't lay eggs like birds, female bats must fly while pregnant and produce only one or -- rarely -- two young per year. Hence, to keep up the populations, bats have developed a long life span of 20 years or more. Wray says that the all-time record was found in a cave in Vermont a few years ago: a pregnant female who had been tagged 27 years before.

Myth: Bats are blind.

Fact: "Bats see as well as you or I," says Hodge.

He admits that's not a lot of help at night, however. Instead of developing sight for their night hunting, bats developed what's known as an "echo-location" system that uses their very sharp hearing (five times more acute than a human's) to send out very high-pitched signals. These ultra-sounds bounce off the bat's prey and allow it to hone in very accurately on the mosquito or moth or whatever it is pursuing. The echo-location system requires very elaborate receptors, and that's why bats have such big ears and bizarre-looking faces.

Early fall is a good time to see bats, partly because of the earlier nightfall and partly because bats must feed now as much as possible to store up for their winter hibernation. That goes on from about November to March in a cave, barn, the eaves of a church (bats in the belfry) or even your attic.

And yes, bats do hang upside-down. "No one really knows why they do," says Wray, but some scientists speculate that it's to protect their very fragile wings.

Myth: Bats are aggressive and get caught in people's hair.

Fact: "Bats are one of the shyest animals in the world," says Wray, "and the most common bat, the Little Brown bat, has teeth so small it actually would have trouble biting through an adult's tough skin."

But if bats are not interested in making us their next meal, why do they swoop so close around us in the evening?

"It's really just the food chain at work," says Hodge. "Humans are walking carbon-dioxide machines. In the evening, flying insects are attracted by that CO2. The bats are attracted to the insects, not to us. Since the bugs tend to buzz around our heads, that's where the bats go, which led to the myth about flying into people's hair."

Myth: Bats can carry and spread rabies without succumbing to it themselves.

Fact: "Like all mammals, bats can and do get rabies," says Wray, "but when they get it, they die, just like any other animal."

The confusion arose some 15 years ago, she says, when a noted bat researcher wrote that bats could carry and spread rabies without getting it themselves. It later turned out that what he had identified was not rabies at all, but a non-fatal malady called "Rio Bravo Virus" whose symptoms were similar to those of rabies.

"He's been trying ever since to get it out of the literature," she says, "but it's pretty much proved impossible."

This is not to underplay the connection between bats and rabies: The 1980 public health statistics showed that bats were responsible for 11 percent of the confirmed rabies cases, behind skunks (63 percent) and ahead of raccoons (6 percent).

Those statistics, however, can be slightly misleading, since bats live in colonies and can spread the disease rapidly among themselves, and also because they are small animals and easy to catch. "The bottom line is that only 10 or 11 people have died of bat-contracted rabies in the U.S. since statistics started being kept," says Wray, "and in at least seven of those cases there was question about whether or not it was a bat that actually inflicted the bite."

Myth: Bats are of no use and should be exterminated when found.

Fact: "Bats are probably the best insecticide around," says Wray, whose bat program includes encouraging people to put up "bat boxes" much as we do bird houses. "A Little Brown bat may eat 3,000 mosquitos in a night." And if that's not enough: Bat guano, she says, makes fabulous fertilizer.

So the next time someone says you're driving them batty, consider it a compliment.