The Land Iguana (Conolophus spp.) is the second biggest land reptile in the Galapagos. It grows up to
four feet long, about a third bigger than its cousin, the marine iguana. Scientists classify the land iguanas
into two species: C. palidus is from Santa Fé Island, while C. cristatus is the other
species. It is found on five or six islands, including. Some islands do not have land iguanas. You can see the
difference in appearance from the photos. It is believed that the land iguanas
evolved from mainland ancestral iguanas that arrived in the islands millions of years ago. Because the islands
are different from the mainland, the Galapagos iguanas evolved considerable differences as they adapted to their
niches.
Galapagos land iguanas are vegetarian, and survive on the driest islands by eating cactus pads (see photo). The adults especially like cactus fruits and will climb the prickly
plants to knock off the fruits then eat them on the ground. If they get the opportunity they will eat carrion
and large invertebrates such as the giant centipede. They get all their water from their food and don't need to
drink. However, they will drink from puddles after a heavy rainfall.
The land iguana seems pretty docile most of the time. This changes during breeding season. The timing varies
from island to island. Males butt heads as they battle over territories, and females fight over good nesting
areas. They reach sexual maturity between eight to twelve years of age. The males that win the biggest
territories end up mating with the most females. Females in the best nest areas have the most success hatching
their eggs. The female digs a long horizontal burrow one or two feet deep and lays up to two to twenty eggs. The
eggs incubate for twelve to sixteen weeks. When hatched the young have to fend for themselves, and are prone to
predators such as the Galapagos hawk, herons and owls. When young they feed on insects and other invertebrates.
Adults are long-lived. Individuals over sixty years old are known from Baltra Island.
The land iguanas are doing well on most islands they occur. Concerns over their conservation status arise from
habitat destruction and predation by feral cats and dogs. On Santiago (James Island) Charles Darwin found so
many iguana burrows he could not find a place to pitch a tent. Today, on this island, there are no burrows and no
iguanas. Donkeys turned loose multiplied to such numbers that they trampled the entire area where iguanas nested
and drove them to extinction. The Galapagos National Park Service has implemented an intensive eradication program
in hopes to restore the native iguana population. This program is nearing completion and has been almost completely
successful at removing the donkeys from Santiago.
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