Like spiders, sea gulls and centipedes, snakes face many obstacles to burnishing their reputation.

For many people, their bad image starts with the story of Adam and Eve and the evil snake in the Bible. And there are plenty of horror movies with giant pythons or anacondas. Even the way they move -- slithering -- conveys sneakiness and untrustworthiness.

But Mike McCaffrey hopes to be a counterforce. At the Hidden Pond Nature Center in Springfield, where he is assistant manager, he tries to change dislike into tolerance. He admires how streamlined they look. No, he says, they won't chase you. They are part of the balance of nature, he points out, helping to keep even less desirable species in check.

"Having respect for snakes is a good thing," he said. "Having the attitude of 'Kill every snake you see' is a bad attitude. It results in more mice. Snakes are better than cats at killing mice."

This is a good time of year to look -- and look out -- for snakes. They are active in the warm months, and some could be seeking mates right now. They are more likely to be in your back yard than you might think. There are snakes that like garages and sheds, snakes that burrow into mulch and leaf litter, and snakes that thrive in piles of wood and in rock walls.

Snakes need food and habitat, though, and if you eliminate those, you reduce the likelihood of having snakes, he said. That means getting rid of wood piles, heavy mulch, stacked rocks or high grass and sealing up building openings. Unless you want snakes.

McCaffrey picked up a baby black rat snake from a display case. It flicked its tongue, which is the snake's strongest sensory organ, the one that tells it whether a warmblooded creature is nearby. Its black skin was covered with white diagonal patches.

Born last fall, it will be an adult in a year. As they grow older and longer -- some reaching eight feet, although that is unusual -- the white patches fade. Their teeth, which curve backward, are designed to grip their prey, so a bite can hurt, but it is not venomous.

"These are the snakes that people see most often," he said. "Juvenile black rats are often brought in dead by people who catch them and think they have a baby copperhead."

In recent years, as the area's immigrant population has grown, McCaffrey has encountered more people who fear black snakes because similar-looking creatures in their homelands are dangerous. The same mistake happens with the local green snake, a harmless variety that to some people from Africa looks like a snake they know to be poisonous.

Black rat snakes like to shimmy up trees during the day, and they go after birds and their eggs. (People with bird feeders, McCaffrey said, should keep this in mind.) In addition to mice, they will eat bigger rodents. Once, McCaffrey found one that had taken down a chipmunk. They kill their prey by squeezing it. Other snakes in this area specialize in catching worms, grubs and bugs, or frogs and salamanders.

At night, black rat snakes come back to the ground to avoid the hawks and owls that enjoy them as a meal. They are also a favorite prey of foxes.

"Foxes use snakes to train their pups how to kill," McCaffrey said. "They bring the snake back alive and have their pups hunt them."

Although most snakes in this area are not poisonous, some are. Copperheads, with a triangular head and butterfly- or hourglass-shaped patterns on their skin, can show up in the back yard, especially outside the Capital Beltway. The timber rattlesnake can live in some of the region's more rural areas. The good news is that cottonmouths, often called water moccasins, do not live this far north.

McCaffrey's attitude when he sees a snake he knows to be dangerous is to keep a respectful distance: "You don't push them," he said, "and they don't push you."

-- D'Vera Cohn

University of Richmond ecologist Joseph Mitchell holds a black rat snake, which kills by squeezing prey.