Alien Iguanas Overrun Florida Island

<< Back to Page 1   Page 2 of 2

By July the panel must submit their plan's budget, which will determine the size of the "iguana tax" Boca Grande residents must pay.

According to Janes, the community has only recently become concerned about the iguanas. He says that in 1997 residents believed the invasive species was harmless and turned down an offer from the county to get rid of the iguanas.

Since then the population has exploded.

The reptiles have no natural predators on the 7-mile (11-kilometer) Gasparilla Island, where Boca Grande is located. (Browse a guide to South Florida reptiles.)

In the past five years the iguana population has reportedly jumped from 2,000 to 12,000.

Biologist Jerry Jackson, of Florida Gulf Coast University in Fort Myers, says a female iguana can lay up to 80 eggs at a time and may do so two or three times during breeding season.

"These animals in their homeland [Mexico] have predators, parasites, and diseases that they didn't bring with them. So their populations here can get out of control," said Jackson, who was hired by Lee County to study the iguana problem.

The biologist says the lizards, which can swim, may have already dispersed to nearby islands. He adds that, if the reptiles reach the mainland, it will be almost impossible to stop their spread.

Bad Pets

It's believed the iguanas were introduced to Boca Grande in the 1970s, when a resident brought a few lizards back from Mexico as pets and later released them.

Jackson says that, unlike green iguanas, which can be tamed, black spinytail iguanas "don't make good pets."

The reptiles use their thorny tails like whips. And once their mouths, which bristle with sharp teeth, clamp down on something, they don't let go.

The sheer number of iguanas on Gasparilla Island—about ten per human resident—is causing a multitude of problems for people and wildlife.

Jackson says the reptiles' feces may carry salmonella bacteria, which can cause food poisoning, typhoid fever, and other ailments. The iguanas also devour sea turtle eggs and shorebird nestlings.

In addition, the lizards dig large burrows, which undermine sand dunes on the island. The dunes help protect people and property from storm surges.

Iguana Vigilantes?

John Bourgoin, who serves on the Lee County iguana advisory board, says he'd like to see a volunteer workforce trap and kill the reptiles.

"We want to take the matter into our own hands," he said, adding that doing so would relieve residents from paying an additional tax.

Bourgoin says money left over from a street-lighting project could pay for the 60 or so traps needed.

"Since the beginning of the year just three of us have gotten rid of about 235 [iguanas]," Bourgoin said.

"So, we're on the right track, I believe."

Jackson, the university biologist, says a much broader effort is needed, including closing off nesting burrows and controlling Brazilian pepper, a non-native shrub with a bright red fruit that is a mainstay of the iguana's winter diet.

"What we've done in the past year is to look at the annual cycle of the animals, and we've been trying to figure out weak points in their natural history," Jackson said.

He said that, by attacking the iguanas in the winter when they're stressed and "getting rid of exotic plants that they are feeding on at that time, we could exercise a natural control on them, to some extent."

Free Email News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).

<< Back to Page 1   Page 2 of 2


SOURCES AND RELATED WEB SITES

ADVERTISEMENT

NATIONAL GEOGRAPHIC'S PHOTO OF THE DAY

NEWS FEEDS     After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.   After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.

Get our news delivered directly to your desktop—free.
How to Use XML or RSS

National Geographic Daily News To-Go

Listen to your favorite National Geographic news daily, anytime, anywhere from your mobile phone. No wires or syncing. Download Stitcher free today.
Click here to get 12 months of National Geographic Magazine for $15.