Amphibian alert!

Natural History, June, 2004

Frogs live almost everywhere--from tropical forests to frozen tundra to scorching deserts. This summer, hundreds of them will be taking up temporary residence at the American Museum of Natural History. Opening May 29, Frogs: A Chorus of Colors will showcase approximately 25 spectacular, vividly colored frog species from around the world in re-created habitats complete with rock ledges, live plants, and waterfalls. The exhibition explores the biology of these popular amphibians, their importance to ecosystems, and the threats they face in the world's changing environments.

Frogs have filled the night with croaks, yaps, grunts, chirps, trills, and warbles since the Age of Dinosaurs; some can be heard from a mile away. Frogs also sport an amazing range of colors, shapes, and sizes: many are more vibrantly tinted than the most dazzling birds, and the largest can grow to the size of a human infant.

Among the fantastic frogs you might see in this exhibition are the dinner plate-sized African bullfrog; the dumpy tree frog that can climb trees and hang from a branch by one toe; the fire-bellied toad that throws its legs into the air to show a bright red underside when it is disturbed; the dart poison frogs, some of which are among the most toxic animals on Earth, containing enough poison to kill ten people (or 20,000 mice); the African clawed frog that looks as though it was flattened in a traffic accident; the Chinese gliding frog whose webbed toes act like a parachute; and the smoky jungle frog that squawks like a chicken. Also see fishlike tadpoles that will later metamorphose into American bullfrogs, sprouting legs and losing their tails.

The exhibition is rich in froggy facts. How do frogs drink.) (Through the skin of their bellies.) What is the world's smallest frog.) (The Cuban robber frog, which grows to a length of only half an inch.) How many eggs does a frog lay.) (From as few as one to as many as thirty thousand, for those that lay eggs--some flogs give live birth.) Do some frogs eat birds.) (Yes indeed.)

Some frogs' skin is covered with a cocktail of protective toxins as a defense against predators, and many of these toxins are remarkably potent in the human body. Scientists study frog toxins for use in human medicine to treat such ailments as heart disease, depression, skin and colon cancers, and Alzheimer's. The phantasmal poison frog from Ecuador and Peru, for example, secretes a painkiller called epibatidine that is 200 times more powerful than morphine--and non-addictive. Chemists are working to perfect a less toxic version of the drug.

Frogs are perhaps the world's most adaptable denizens. There are more than 4,000 species of them, and they live on every continent except Antarctica. But over the past 50 years, scientists have recorded precipitous declines in frog populations, with some species vanishing completely. Frogs are delicate creatures, and are often the first casualties when pollution or human activity affects a habitat, making them important barometers of environmental change and giving an early warning for endangered ecosystems. Many frogs are also useful in other fields of scientific study: their transparent eggs offer embryologists a chance to watch single cells grow into wriggling tadpoles, and scientists have also used frogs to study muscle function, perform pregnancy tests, and experiment with cloning--the first frog was cloned 30 years before Dolly the sheep.