Conolophus subcristatusGalapagos Land Iguana

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Geographic Range

The Galapagos Land Iguana is native to the Galapagos Islands, off the coast of Ecuador. It is formerly widely distributed on these islands, though its numbers are now greatly reduced (Mattison 1989, Cogger and Zweifel, 1998).

Habitat

The lizards live in land burrows, which offer protection from the hot sun. Many islands on which the iguanas live are quite arid.

Physical Description

The Galapagos Land Iguana is yellow or brown in color with spots throughout its ventrum and dorsum. A spikey dorsal crest runs along the neck and back. This is a large (>48 in), heavy bodied lizard, with thick back legs and smaller front legs. There are long, sharp claws on its toes. It has a short blunt head and pleurodont teeth. Its tail is quite a bit longer than its trunk. (Mattison 1989).

Reproduction

These lizards have a mating ritual where the male agressively courts the female. Males defend territories around their burrows that both they and females use as shelter, and most courtship occurs around these burrows. Females are attracted to male's territories with burrows, but these burrows are not used for nesting. (Werner 1982).

Female Land Iguanas lay soft-shelled eggs with permeable shells. About 25 eggs are laid in burrows in moist sand or under leaf litter. On the arid, rocky island of Fernandina, females may travel more than 15 km to find good nest sites, sometimes within the crater of a dormant volcano. When places to lay eggs become scarce, competition between females occurs and some eggs already laid may be disturbed by another iguana (Werner 1983, Mattison 1989). Hatchlings appear in about three to four months, and may take about a week to dig out of the nest cavity (Terraquest 1996).

Lifespan/Longevity

Food Habits

The Land Iguana is largely a vegetarian. The prickly pear cactus (Opuntia) is a major food source; the lizard eats the cactus fruit and leaves by moving the cactus around in its mouth until all the spines are worked off (Mattison 1989).

Economic Importance for Humans: Positive

This species was observed by Darwin early in the 19th Century; Darwin noted its similarity to iguanas on the South American mainland, as well as its obvious adaptations to local conditions. These and other observations of Galapagos wildlife contributed in part to Darwin's theory of evolution.

Today the Land Iguanas are an important part of the unique Galapagos fauna, and studies of their biology, as well as conservation programs, are continuing.

Economic Importance for Humans: Negative

No adverse effects.

Conservation Status

The Galapagos Land Iguana is listed as a threatened species by the World Conservation Union (Baillie and Groombridge 1996). Threats include destruction of eggs and young lizards by introduced rats and cats, and destruction of food plants by introduced goats.

Contributors

Tami Bruin (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

scrub forest

scrub forests develop in areas that experience dry seasons.

References

1996. "Wildlife-Coastal Zone-Land Iguanas" (On-line). Accessed November 10, 1999 at http://terraquest.com/galapagos/wildlife/coastal/landiguana.com.

Baillie, J., B. Groombridge. 1996. 1996 IUCN Red List of Threatened Animals. Gland, Switzerland: IUCN.

Cogger, H., R. Zweifel. 1998. Encyclopedia of Reptiles and Amphibians. San Diego, CA: Academic Press.

Mattison, C. 1989. Lizards of the World. New York, NY: Facts On File, Inc..

Werner, D. 1983. Reproduction in the Iguana Conolophus subcristatus on Fernandina Island, Galapagos. American Naturalist, 121: 757-775.

Werner, D. 1982. Social organization and ecology of land iguanas. Pp. 342-365 in G Burghardt, A Rand, eds. Iguanas of the World. Park Ridge, NJ: Noyes Publications.