Bats. The word conjures visions of unspeakable visitors from the crypt, intent on sucking blood, causing rabies, nesting in curly locks.

That strange, spectral fellow with cape, hairy palms, pale skin and nocturnal ways flutters to mind.

Get a broom . . . or a stake.

But bats get a bad rap, according to Dr. Merlin D. Tuttle, who should know. He is the best local version of Bruce Wayne, aka Batman, anywhere.

Officially, Tuttle is curator of mammals at Milwaukee's Public Museum, a friendly place of knowledge in Wisconsin's cleanest big city. But when trouble comes knocking, Tuttle is transformed into his other identity: world expert on Chiroptera (bats) and founder and chief executive of Bat Conservation International.

Perhaps not since Don Facundo Bacardi put a bat as a trademark on his first bottle of rum in 1862 has the winged mammal had so staunch a champion as Tuttle. From a crowded office on the sixth floor of the museum, he has almost single-handedly sparked awareness of the endangered situation of the world's bats.

"They are smart, sweet-tempered and in trouble," Tuttle said. "Most of what you hear about bats giving people rabies is just plain false. You stand a greater chance of getting food poisoning at the church picnic than you do getting rabies from a bat." Only a few cases of rabies are known to have been transmitted to humans by bats in the last several decades, he said.

The 41-year-old zoologist has studied bats all his life and throughout the world. There is plenty to study: There are more species of bats -- nearly 2,000 -- than of any other mammal. They range from a bat the size of a bumblebee to the flying foxes of Australia, with wing spans as large as six feet. Most are either insectivores or eat fruit and nectar. Some species are carnivores; only the South American vampire lives on animal blood.

Hundreds of bat species are in trouble, under attack from humans seeking food, fun and profit. From Australia to Kenya, South America to Western Europe, Samoa to Canada, Tuttle said, bats crucial to insect control and plant pollination are being killed.

Insecticides in developed countries have decimated bat populations, and the trouble is spreading to Third World countries. Yet fruit- and nectar-eating bats are crucial to pollination in tropical regions, he said, adding far more in benefit than they damage produce.

In the last two decades in the United States, he said, millions of Indiana and gray bats in the Southwest and Midwest have died from attacks by hunters, pranksters and professional exterminators ignorant of the bat's unique niche.

Tuttle cited one cave in the Southwest that 20 years ago was home to more than 10 million gray bats. Today, fewer than 100,000 bats live there.

"Those animals used to clean up 250,000 pounds of mosquitoes and other insects a night," said Tuttle, his voice tinged with wonder. "Now, the insects have it all to themselves."

The U.S. Fish and Wildlife Service estimates that one gray bat consumes as many as 3,000 insects a night. The gray bat is on the endangered species list.

Part of bats' problem is their life style. By congregating in huge colonies in caves, they are especially vulnerable to attack. "One cherry bomb thrown by a kid into a cave can kill hundreds of thousands of bats," Tuttle said. "If they are disturbed in the winter, when they are hibernating, they may lose 10 to 30 days' worth of stored energy." By spring, tens of thousands may have died.

Tuttle's comments were strengthened by the presence of two persuasive assistants in his office: two African fruit bats hung upside down from perches. With a little cajoling and the promise of some orange juice, Ding, the friendly fruit bat, left his perch to nestle in Tuttle's hand.

Up close, Ding looks exactly as menacing as "E.T." About six inches long with wings folded, the animal has large, fawn-like eyes, shell-like ears that quiver with interest and apprehension and a gentle muzzle with a long, pink tongue to lap juice or curl around a banana slice.

The bat will never rival Ling-Ling the panda for being perceived as cuddly and thus worth saving but, largely because of Tuttle's efforts, the bat's image as most reviled creature in the Western world is unexpectedly being transformed to that of a powerful and sympathetic new symbol of animal conservation.

Tuttle's Bat Conservation International is the principal vehicle for the effort, and one of his largest contributors is Bacardi Imports Inc. of Miami, the import arm of the rum distiller. A stylized bat still appears on every bottle of Bacardi.

Bill Walker, president of Bacardi Imports, said a company brochure extolling bats' virtues has been unusually popular.

"I didn't know the bat was so beloved. I wasn't really aware of the facts. Some bats are as cute as puppy dogs, and others are homely as hell . . . . [But] we want to protect our trademark," he said.