The two species of land iguanas endemic to the Galapagos are the only two species of the genus Conolophus. They are among the most primitive members of the iguana family. Conolophus subcristatus (Galapagos land iguana) is native to six of the islands, and Conolophus pallidus (Santa Fe land iguana) is found only on the island of Santa Fe. Both inhabit the arid regions of the Galapagos Islands, where they sleep in land burrows to conserve their body heat at night.

The Galapagos land iguana feeds on cacti (mainly the prickly pear cactus) and their flowers. It suffers no adverse affects from eating cactus spines, which pass easily through its digestive system. It is not unusual to see them sitting under a cactus, waiting for pieces to fall. They normally use their front feet to scrape the larger thorns from the pads, but they don't seem to mind the smaller thorns. Usually they will gulp down a cactus fruit in just a few swallows. Like other iguanas, the juveniles feed primarily on insects.

This lizard averages 1.2 m (4 ft.) in length. It is yellowish with brown blotches on its sides and legs, and has a spiny crest running dorsally from its head.

Galapagos land iguanas are territorial and signal their aggression with head-nodding. The male aggressively courts the female. Following copulation, the female flees and finds a spot to dig a nest in which to bury a clutch of up to 25 eggs.

When Charles Darwin visited the Galapagos Islands in 1835, he found so many Galapagos land iguana burrows that he had to tread cautiously. Today, very few of these iguanas exist. Humans have introduced a variety of domestic animals to the islands, including goats, which have eaten the protective undercoat of vegetation, thereby exposing young lizards to birds of prey.