Iguanas: head for the hills: these endangered Jamaican lizards, once thought extinct from the islands, are making a comeback through projects aimed at conservation and protection.

• Author: Cohn, Jeffrey P.

One hot and sunny June day, Byron Wilson walked briskly through the Hellshire Hills region of Jamaica about a dozen miles west of Kingston. He watched his steps carefully as he traversed steep cliffs, side-stepped deep sinkholes between rocks, and avoided the ever-present slabs of hard, jagged limestone that could rip apart clothes and tear even the sturdiest of hiking shoes. Overhead, shafts of sunlight filtered through frequent openings in the forest canopy, bathing the aloe-and-cactus covered ground below in bright light.

Suddenly, Wilson, a lecturer in conservation biology at the University of the West Indies in Kingston, stopped in his tracks. Ahead of him, several Jamaican iguanas were digging furiously in a patch of bare, reddish-colored soil. Despite Wilson's presence, the iguanas kept digging. They were females fulfilling an age-old reptile imperative to dig tunnels in warm soft dirt to make a place to deposit and incubate their eggs.

Jamaican iguanas are the largest living land animal native to that Caribbean island. Adult males, the larger of the sexes, can reach nearly five feet in length. The iguanas range in color from an olive green to slate blue. A bluish-green dorsal crest runs from their heads and shoulders down their back. Females sometimes appear reddish-brown after digging in Hellshire Hills dirt. Males have a loose flap of skin hanging under their necks called a dewlap; they can extend it to impress females.

As a group, iguanas are the New World's largest lizards. They range from the southwestern United States to the Caribbean and most of Central and South America, as well as some Pacific Ocean islands. Some dwell in trees in tropical forests where they feed on leaves, fruits, flowers, and buds. Others live in deserts. And one, the marine iguana of the Galapagos Islands, inhabits rocky seashores and eats algae and other vegetation growing on submerged rocks in coastal waters.

Once common, Jamaican iguanas are now confined to Hellshire Hills. Although no one knows for sure, they probably number no more than 150 in the wild. Their future is uncertain. Still, the fact that the Jamaican iguana has survived at all points to one of the Americas' most successful conservation stories. And the effort to save Jamaican iguanas also protects Hellshire Hills, one of the few dry tropical forests remaining in the Caribbean. Hellshire Hills is home to more than 300 native plants, including 53 found nowhere else on Jamaica, says Allison Alberts, the San Diego Zoo's director of conservation.

The Jamaican iguana is one of nine (or sixteen, depending on how you count or who you ask) species of iguanas known as rock iguanas. Rock iguanas were once found throughout the Caribbean and West Indies, but they are now threatened with extinction almost everywhere they live. One, the Nayassa Island iguana, is gone. Burgeoning human population and development has destroyed much of their habitat and fragmented most of what remains. Goats, pigs, and sheep introduced to the area now compete with iguanas for food and trample their nest sites. Mongooses, cats, and dogs kill the lizards, and rats eat their eggs.

The Jamaican iguana was believed to be extinct by the 1940s. None had been seen on Jamaica itself for decades and even a small population on an offshore island had disappeared, says Peter Vogel. Vogel is a senior lecturer at the University of the West Indies who served as the first chairman of the Jamaican Iguana Recovery Group, a coalition of government agencies, conservation organizations, zoos, and universities that works to conserve the iguana and its habitat.

The first clue that Jamaican iguanas might still exist came when a dead animal was found in the 1970s. Nothing happened then, and no others were seen for years until local resident Edwin Duffus--who had been out with his dog illegally hunting feral pigs--captured a live iguana in Hellshire Hills in 1990.

The Jamaican iguana's rediscovery was "pretty big news for the conservation community," says Wilson...