Land Iguana Types
In The Galapagos Islands

The Galapagos Islands land iguana types are another classic example of evolution caught in the act. Adult sizes range from 1 to 1.5 meters long (3 to 5 feet) and they can weigh up to 10 kilograms (35 pounds). There is a good deal of variation between the adult sizes, colors and age of maturity between the different islands. This shows us that if given more time these iguanas will, like the Galapagos tortoises, evolve into separate species with different physical features.

This has already happened to the original iguana arrivals to the islands. As you can see in the picture below, the ancestral iguanas split about 10 million years ago into both mainland and marine iguanas. Later the mainland iguanas speciated again and gave rise first to the recently studied pink iguana and then again to give the two current species of yellow land iguanas.

These two species have the same diet and nesting behavior, but the Santa Fe iguanas are a paler yellow and have longer more tapered snouts. Their dorsal spines are also more obvious. Because of their paler color the Santa Fe iguanas are called Conolophus pallidus.

The existence of the pink iguana Conolophus rosada on only one area of a volcano on the largest and fairly young island of Isabela has presents problems of its own.

Diet

The main diet of all three species is the prickly pear cactus. This food also gives the land iguana the water it needs. Land iguanas can survive an entire dry season without needing to drink fresh water.

These creatures occasionally eat other things like carrion, worms or insects, as the opportunity arises.

Reproduction

As with the marine iguanas, the land iguanas lay their eggs in burrows dug in the soft soil, and they too guard the clutch for some weeks after laying. They do not guard them for the whole incubation period of 3 to 4 months, and when the hatchlings dig their way out of the nest they are on their own.

Populations from different islands reach maturity at different ages. The range is between 8 and 15 years and they have an estimated lifespan of 50 to 60 years.

Threats To The Iguanas

The sad and familiar story of feral animals destroying the native populations is repeated again with the land iguanas. Cats and dogs kill the adults. They also dig up nests and eat eggs and young lizards. Rats also join in with the egg feast.

Many of the island populations of iguanas have been decimated, though the Galapagos National Parks Service is working to eliminate the feral animals and boost population numbers through captive breeding programs.

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