BATS' NEW IMAGE

If ever a creature seemed conjured by the forces of darkness, it is the bat. With webbed wings and feral face, the furry little beast appears to be the offspring of some monstrous union of bird and rodent. Over the years, legend has had it that bats are filthy and nasty (they feed on human blood) and that they possess spooky supernatural powers (they shift shape from bat to man). No wonder they have been a motif of countless horror tales and films.

This image, however, is the product of imaginative folklore, stubborn myth and terrible p.r. The bat, say scientists, is actually one of nature's most dazzling and precious creations. Today researchers are striving to correct common misapprehensions about them--and racing to save them from extinction. Last week in Boston, the largest ever convocation of bat experts met to trade new findings from the weird and wonderful world of bats. Among recent discoveries:

While most species of bats live in vast colonies in caves or trees, some nest in spider webs; others fashion "tents" out of leaves. In southern India, for example, the male short-nosed fruit bat spends as long as two months painstakingly chewing the veins of leaves and palm fronds until they collapse into a shelter that will house him and a harem of as many as 20 females.

Bat pups can weigh as much as a quarter of their mother's heft--the equivalent of a 100-lb. woman giving birth to a 25-lb. baby.

Most mammals wean their young when they reach 40% of adult size, but bats continue nursing their offspring until they are almost fully grown. The reason: pups need the extra time to attain the large wingspan and wing surface required to fly.

Bats' built-in echolocation system is so finely tuned that it can detect insects' footsteps, changes in air currents caused by vibrating insect wings, even the ripple in a pond as a minnow's fin breaks the surface.

According to the fossil record, bats were soaring in the sky at least 55 million years ago. These ancient flyers, says evolutionary biologist Nancy Simmons of New York City's American Museum of Natural History, were "virtually indistinguishable from today's echolocating bats." Though laymen think they most resemble rodents, bats' closest cousins are primates. Modern bats are amazingly diverse; about 1,000 species account for nearly a fourth of all mammal species. The only known group of flying mammals, they range in size from Thailand's tiny bumblebee bat, weighing less than a penny, to Indonesia's giant flying fox, with wingspans of nearly 6 ft. Many bats feed on insects, while others prefer fruit, nectar or pollen. A few feast on fish, frogs, rodents and, yes, blood. Contrary to legend, however, vampire bats, which dwell in Latin America, suck the blood of grazing cattle and horses, not sleeping humans.

Essentially docile, bats play a vital role in maintaining ecological balance. For one thing, they protect crops from marauding insects. The 20 million Mexican free-tailed bats that roost in Bracken Cave near San Antonio, Texas, from spring to fall consume 250 tons of insects every night as they swarm to altitudes of 10,000 ft. Farmers are not the only ones who benefit. A single little brown bat can speedily clear a suburban backyard of pesky mosquitoes, lapping up 600 bugs an hour.