Frog man

Ian Hiler has more frogs than friends. Not just green frogs, but blue frogs, red frogs, yellow frogs, black frogs, frogs with spots, frogs with stripes, frogs that cry "EEEEEyat! EEEEEyat!" with the afternoon rains, and even frogs that lay eggs in trees.

His apartment in New Orleans's warehouse district looks and sounds like a tropical rain forest. Mr. Hiler gets full use of the bathroom, kitchen, and bedroom, but the frogs get the rest. Eight terrariums line the walls of his living room, which has two large windows to let in sunlight. The light feeds the plants crammed inside the frog tanks. Visitors are uncertain if they're in an urban house or a distant jungle.

"My first job was in a fish store," Hiler says, "but I always liked amphibians on the side." Amphibians - animals such as frogs, toads, newts, and salamanders - are coldblooded creatures that need to keep their skin moist. Hiler's specialty is poison-dart frogs.

Poison-dart frogs are amazing amphibians. They live in the hot jungles and tropical forests of South and Central America. Their name comes from the poison they carry in their skin, poison that native tribes use for hunting.

Dart frogs are tiny - no more than two inches long. Most live in shrubs and leaf litter, but some spend their whole lives in trees. They feed on all types of small insects. Most important, they eat ants. The ants in the dart-frogs' habitat feed on leaves that contain a poison to kill bugs. The ants are able to break down the poison and when the frogs eat the ants, they get a small amount of poison from the ant's digestive tract. The poison is stored on the frogs' skin. Now the frogs are poisonous, so they're safe from hungry snakes and birds that like the taste of other frogs.

"That's why these frogs have such bright colors," Hiler says. "The colors are an alarm signal that say 'Stay away! I'm poisonous!' "

Because the frogs contain poison, very few animals can eat them. (A few snakes are immune to the poison.) But the natives in the area have found an interesting use for them. Hunters take an arrow or blow-dart and rub the tip across the back of a frog to scrape off some poison. This poison proves deadly when the arrow is shot into a bird or monkey.

Dart frogs come in more colors than a large box of crayons. You can find more than 400 types of dart frogs. Scientists study them to understand how new species form in the wild.

"My tribe is Tinctorious," Hiler says. Tinctorious is a group of poison-dart frogs that includes six species. Hiler has bred them all. At the Audubon Aquarium of the Americas where he works, Hiler puts together terrariums so the public can gape in awe at the tiny, living jewels. The frogs climb the plants and glass sides of the terrariums while moms, dads, and kids peer in and shriek with delight. But what most people don't get to see is the breeding facility that Hiler runs about a mile away, just outside New Orleans's French Quarter, inside a nondescript warehouse.

"Thank goodness, I work at an aquarium," Hiler says. "Otherwise, I wouldn't have anywhere to keep all my frogs." At the frog-breeding facility, Hiler has set up two rooms for the frogs. In one room he keeps pairs of frogs (one male, one female) in separate terrariums. Poison-dart frogs are very territorial and will kill other frogs that enter their patch of rain forest.

"Under here, you can see where they lay the eggs," Hiler says. He turns over the saucer from a clay flower pot to reveal a piece of plastic with frog eggs stuck to it. The plastic substitutes for a leaf on which frogs would lay their eggs in the wild. Most frogs lay their eggs in water. But laying eggs on leaves is not the only weird thing that dart frogs do. The father guards the eggs and brings water to keep them wet. Once they hatch, it really gets strange.

"They climb on the father's back and hold on with these special suckers they have on their mouths," Hiler says. "The father then takes them to a small puddle where the tadpoles grow into adults."

As soon as Hiler's frogs lay eggs, he removes the eggs to the tadpole room. Each egg goes into its own aquarium with a few inches of rainwater in it. Dart-frog tadpoles excrete chemicals that kill other tadpoles, so Hiler keeps them all separate. The tadpoles each get a small sprinkle of fish food twice a week. The aquariums are stacked on a shelf with the younger tadpoles on the bottom shelf. As the tadpoles get older they are moved to higher levels until they begin sprouting legs. Hiler then moves them back into the frog room and makes sure they have a small gravel beach to climb onto.

Captive-raised dart frogs make better display animals than wild-caught specimens. Without their poison-ant diet, Hiler's frogs are not poisonous. The colorful amphibians are in high demand. Hiler has traded them with zoos all over the world, in exchange for animals such as stingrays or sharks. (He almost traded frogs for some penguins, once.)

"I've raised some frogs for almost four or five generations; that's about 15 years in captivity," Hiler says. "These frogs are just the most interesting things I've ever encountered," he adds. "And they're really beautiful. I guess I'll keep breeding them forever."

Frogs lay their eggs in early spring. The eggs are found floating in shallow water, stuck to one another and anchored to a water plant. They are nestled in a jelly which, when exposed to sunlight, keeps the eggs slightly warmer than the water. Growth from egg to frog takes from five weeks to two years, depending on the species.

A young polliwog

A newly hatched tadpole soon develops external gills and a mouth.

'Teen' polliwog

Next to appear are the hind legs, and then joints. The tadpole soon loses its external gills as lungs start to develop.

Froglet

Forelimbs appear, the tail shortens, and the eyes enlarge and develop lids. The tongue grows, and many other changes occur.

Adult frog

In most species, metamorphosis is complete by late spring or early summer. Frogs hibernate out of the water from fall until spring. They reach sexual maturity after about three years.

Some 90 frog species inhabit North America, and at least two or three types probably live near you. Fully mature frogs are difficult to keep, but their young are easy to raise and can make for an exciting science project.

Baby frogs look like little fish with fat heads and flat tails. You can usually find them during spring in still water, such as a pond or near the edges of lakes or ditches. Frogs lay their eggs in a large jelly-like mass that might contain up to 300 eggs.

When the eggs hatch, the polliwogs (as they're called) feed on decaying plant material until they go through metamorphosis and become frogs. The process can take from five weeks (for some desert species) to two years (for large bullfrogs).

Frogs have been dying out in many areas of the world. The reason for this is not known, but scientists suspect that pollution is killing polliwogs. If you want to help frogs, frog specialist Ian Hiler suggests digging a small pond in your backyard, if you've got room (and your parents' permission!). Pond "kits" can be found at many hardware stores. If you fill your pond with water plants, you may encourage frogs to lay eggs in them.

It's fairly easy to raise frogs from tadpoles, but be careful! The biggest mistake you can make is trying to raise too many of them. The second big mistake is overfeeding them. Here are Mr. Hiler's rules for raising frogs:

1) Get a small aquarium (five- or 10-gallon capacity), and fill it up with a few inches of rainwater or water from a pond. Tap water and even bottled water sometimes contains chemicals that can hurt tadpoles. In a pinch, Hiler says, use bottled water that has been allowed to sit in the tank for a week. You don't need a filter, and the water does not need to be changed.

2) Put two or three tadpoles in the tank. (No more! Otherwise, you may kill them.)

3) Put the tank in a place where it's away from heating or cooling vents and out of direct sunlight.

4) Feed twice a week with a small sprinkle of fish food. Do not overfeed!

5) The frogs' hind legs will sprout first. When the front legs start to grow, it's time to build a beach. The frogs need a section of the tank with a sloping bank so they can climb onto land. Keep it simple: Build the hill out of clean gravel.

6) Eventually, the tail will start to shrink as the froglet absorbs it. Find a good spot to release your froglet: Choose a place near where you caught your polliwogs, or somewhere close to standing water. Release your frogs back into the wild. Don't try to keep them as pets.

7) Clean your tank with a mild detergent. Rinse it well, and let it air dry thoroughly. Now you're ready for next spring, when the frogs begin to chirp.