Land Iguanas

Courtesy of The Charles Darwin Foundation for the Galapagos
and The Galapagos National Park Service

Land Iguanas resemble mythical creatures from the past - dragons with long tails, clawed feet and spiny crests. In reality these harmless lizards are alive today, but endangered in their own native land - Galapagos.

TERRITORIALITY
The males defend specific areas, which usually include more than one female. Male iguanas can be highly aggressive towards each other. Territorial displays involve rapid nodding of the head and, sometimes, biting and tail-thrashing battles.

Land iguanas reach maturity between 8 and 15 years of age, depending on their size. They congregate and mate during specific periods, which vary from island to island. The females then migrate to suitable areas to nest. After digging a burrow about half a meter deep, the female lays 2 to 25 eggs in the nest. She then defends the burrow for some time to prevent other females from nesting in the same spot.

The young iguanas hatch 3 to 4 months later and then take about a week to dig their way out of the nest. These tiny, speckled iguanas can easily fit in the palm of a hand. If they survive the difficult first years of life, when food is often scarce and native predators such as hawks and owls are a danger, land iguanas can live for more than 60 years.

ADAPTABILITY
Distantly related to the green iguana of the South American continent, Galapagos land iguanas can be over a meter long with males weighing up to 13 kilograms. Their rough, wrinkled skin is yellowish with scattered patches of black, brown and rust. Two species occur in Galapagos - Conolophus subcristatus is native to 6 islands, while Conolophus pallidus is native only to Santa Fe.

Land iguanas live in the drier areas of the islands and in the morning are found sprawled beneath the hot equatorial sun. During the midday heat, however, they seek the protective shade of cactus, rocks, trees or other vegetation. To conserve their body heat at night, they sleep in burrows that they dig in the ground.

Lang iguanas are very flexible in their diet but generally depend on low-growing plants and shrubs, as well as the fallen fruits and pads of cactus trees. Although they often scrape the spines off cactus pads with their claws, it is not uncommon for an iguana to bite into a cactus pad, spines and all! These succulent plants provide them with most of the moisture they need during long dry periods.

POPULATIONS WERE DRASTICALLY REDUCED
When Charles Darwin visited Galapagos in 1835, he wrote about the abundance of the land iguanas. "I cannot give a more forcible proof of their numbers, than by stating that when we were left at Santiago Island, we could not for some time find a spot free from their burrows on which to pitch our single tent".

However, when whalers and settlers started visiting Galapagos in the early 1800's, they brought with them goats, pigs, dogs, cats and other domestic animals. Over time these animals escaped or were abandoned with drastic results. Cats hunt the young iguanas and dogs kill adults. Goats wipe out entire areas of vegetation that the iguanas depend on for food. Today, the abundant iguanas that Darwin wrote about on Santiago Island are extinct. On some of the other islands they are nearly gone.

RESCUE OPERATIONS ARE SUCCESSFUL
In 1976, wild dogs wiped out a colony of almost 500 land iguanas at Conway Bay on Santa Cruz. Together, the Charles Darwin Research Station and the Galapagos National Park Service, launched an emergency rescue operation for the 60 or so survivors. Shortly thereafter, another large-scale attack occurred at Cartago Bay, Isabela Island, and 30 more iguanas were rescued.

These rescue operations marked the beginning of a captive breeding and rearing program for land iguanas at the Station and Park headquarters on Santa Cruz. There, the eggs from endangered populations of iguanas are incubated. The young are raised until large enough to be safely returned to their island of origins. In the 1980's, adult iguanas that had been moved from Baltra to North Seymour in the 1930's were added to the breeding stock. In 1991, captive-bred land iguanas were repatriated to the island of Batra, where they had been extinct for more than 50 years. Since 1980, over 700 young iguanas have been released back into the wild.

The captive breeding program is reinforced by an on-going campaign for the eradication and control of introduced animals throughout the islands. The populations of wild dogs were eliminated from Cartago and Conway Bays, and goats were removed from several small islands, while pigs and wild cats are now controlled on others. The program has been such a success at Cartago Bay that all of the adult iguanas were repatriated in the early 1990's. However, vigilance must continue.

THEIR FUTURE IS IN YOUR HANDS
The land iguana program is funded by the Ecuadorian Government, World Wide Fund for Nature, Friends of Galapagos and other concerned institutions and individuals. Although much has been accomplished, much remains to be done. The continuation of research and the rearing program are essential for the survival of the land iguanas. The control of introduced animals is necessary to prevent further damage to land iguana populations and their habitat.

The Galapagos Iguana is unique. Continued conservation efforts and supports are essential if this strange, crested reptile is to be saved from extinction.

There is only one Galapagos. Help us protect it for the future.