The beast beat.

Meet four scientists who love to work with creatures some people love to hate. You'll be amazed at the adaptations - survival traits - that make even the creepiest critters cool.

GONE BATTY

Merlin Tuttle recently made an unusual purchase. He bought a bat cave near Austin, Texas. There's no cool car or high-tech computer inside. But there are bats - 20 million of them.

Some people believe that bats are unclean, disease-carrying, blood-sucking "vampires." But Tuttle, a chiroptologist (bat scientist), says "none of these statements is true." Of the 1,000 bat species in the world, only three are blood suckers, he says. These vampire bats live in Latin America and prey on cattle, horses, and fowl - not humans.

The remaining 997 bat species actually help humans. For instance, some of these bats, no bigger than your hand, can eat 600 mosquitoes in an hour! "Bats are one of the primary predators of insect pests in the world," Tuttle says.

Other bats survive by taking a bite out of nectar-filled flowers and fruits. In the process, they pollinate thousands of flowers and can scatter 60,000 seeds in a single night. Those seeds, says Tuttle, help replant rain forests and the bats' own food supply.

Bats are well adapted (built to survive) in their old-growth forest and cave habitats, Tuttle says. But unfortunately people are destroying these habitats to build on the land - and out of fear. Now 40 percent of bat species are endangered, Tuttle says.

That's why he bought his bat cave - to help rescue endangered bats. Tuttle also directs an organization called Bat Conservation International, based in Texas, and visits threatened bat habitats worldwide. His main aim: to change "bad bat publicity."

SPIDER SOCIETY

Leticia Aviles hunts down spiders twice a year in Ecuador, her native country. The spiders she seeks are called social spiders because they live in groups.

"Social spiders are unusual because they cooperate to build nests, reproduce, and catch prey," Aviles says. Most spiders aren't like that. In fact, if you put a group of "antisocial" spiders together they will eat each other, Aviles says. "But social spiders won't eat each other even if they're starved."

A social-spider colony usually contains thousands of spiders. "Together they build webs using their silk, branches, and leaves," Aviles says. By joining forces, these spiders can catch and carry an insect (e.g., a cockroach) that is several times their size.

Social spiders, like other spiders, don't really eat their dinner - they drink it. First they inject their victims with venom to paralyze them. Then the spiders vomit digestive juices all over the prey. The juices dissolve the prey so that it becomes liquid. Then the spiders drink up. Insect Slurpee, anyone?

Ron Sawyer handles big, slimy, blood-sucking worms all day long. Sawyer and partner Lisa Seale run Biopharm, a leech farm in South Wales, Great Britain. "We breed leeches and send them to doctors in hospitals around the world," says Seale. According to these farmers, doctors use their leeches to help restore patients' blood circulation.

"Leech saliva contains an anticoagulant, a protein that prevents blood from clotting," Seale explains. The anticoagulant is an adaptation that helps leeches survive, says Seale. When these parasites (organisms that feed off other living things) bite into their hosts (fish, frogs, or birds), the chemical keeps the leeches' bloody meal flowing.

During the 19th century, doctors took advantage of this trait by letting leeches suck blood from patients. This "bloodletting" was supposed to get rid of the patients' "diseased blood" - and cure illness.

The technique wasn't always successful; some patients died from excessive blood loss. But now leech treatment is making a comeback.

"Doctors today use European or Asian leeches to prevent or break up blood clots that may develop after surgery," says Seale. When blood clots form in veins, blood pumps into the damaged tissues, but not out, Seale explains. That leads to blood buildup and swelling in the tissues. The leech helps suck out the excess blood and restore circulation. A chemical in the leech saliva then keeps the patient's blood flowing clot free for up to 10 hour-s after the leech stops feeding, Sawyer adds.

Leech treatment may look painful, says Seale. But she insists it's not. That's because leech saliva also contains an anesthetic, a chemical that causes a loss of sensation. "It's basically another survival mechanism for the leech," Seale explains. "If you felt a leech biting you, you'd brush it off and the leech wouldn't be able to feed." The anesthetic allows the leech to suck your blood pain free.

Fortunately, leeches don't eat much - or often. They'll slurp up only five times their body weight once a year, Sawyer says.

SNAKE SLEUTH

I was a little queasy the flat time I handled a snake," says Barbara Savitzky, a reptile scientist (herpetologist) at Christopher Newport University in Virginia. In college, Savitzky studied animal behavior, which required taking care of snakes in the lab. After handling the snakes for a while "I became fascinated by them," she says.

Now Savitzky studies these slithery reptiles for a living. "I just finished working on a project with the Virginia canebrake and copperhead snakes," she says. She wanted to study the snakes' habitats and reproductive behavior. But because snakes coil up and have patterned skin they blend into their environment. These traits keep snakes safe from predators, but also make them hard to find. So to keep tabs on the reptiles, Savitzky explains, "we surgically implant radio transmitters inside snakes in the lab, and then release them into the wild."

Once in the field, Savitzky tracks down the snakes through signals emitted on her radio, she says. So far she's found that canebrakes live inside tree-root holes, mate in early spring, and give birth to live offspring (unlike many other egg-laying snakes).

To find out what the snakes eat, Savitzky sometimes catches a reptile and surgically opens its stomach to see what lies inside. Her most popular finds: squirrels and wild rats.

To catch a meal, the snakes bite down on their prey and inject venom with their sharp, hollow fangs, says Savitzky. The venom dissolves the prey's insides, which makes the prey easier for the snake to digest, she says. Still, the snakes can take about 10 days to digest a squirrel.

Some snakes do eat larger animals. Pythons have been know to pack away a whole antelope or crocodile! But none normally prey on humans.

Still, working closely with the reptiles can be dangerous. "A rattlesnake once bit my hand while I was trying to feed it in the lab," Savitzky says. "I stayed calm and used a syringe-like device to suck out the poison. We keep the Extractor in the lab - just in case."