Rafting Iguanas.

Iguanas catching waves as they raft across the Caribbean? Incredibly, in September 1995, 15 green iguanas were swept out to sea after hurricane Luis blasted the island of Guadeloupe. The lizards clung for life to a mat of uprooted trees for some 320 kilometers (200 miles), until one month later they washed up on the island of Anguilla (an-GWI-luh). Local fishermen who spotted the iguanas surfing ashore were stunned.

"This was a major invasion," says Ellen Censky, a herpetologist (reptile expert) in Anguilla. Now, after three years, Censky and a research team have documented the progress of Anguilla's newest residents. While the rafting iguanas were weak and dehydrated at first, they soon recuperated. Censky and her team caught and marked seven of the iguanas right after their arrival, and have tracked them ever since.

Now, a pregnant female iguana has led herpetologists to conclude the Anguilla iguana population is healthy and quite comfortable in their new home. Even more in. triguing, this research offers scientists the first clear-cut answer to an age-old riddle: How do animal species manage to disperse or scatter their populations around the world, especially on remote island chains?

"Many scientists never believed such incredible journeys like this were even possible," says Censky.

"Now we have concrete evidence."

The evidence also supports some biologists' theories that rafting is one way animals--including mammals--disperse throughout island chains. "Just think of all the storms in all the millions of years--and there's a real probability of animals getting anywhere in the world," says evolutionary biologist Blair Hedges at Pennsylvania State

Some biologists also think ancient land bridges between islands or even continents offered another route that animal populations used to migrate, or move from one place to another. Ah, home sweet home.