Marine Iguana

Marine Iguana From Blane Peruns TheSea.Org
Credit: BRJ INC.
The marine iguana is an unusual reptile that lives and feeds in the waters of the Galapagos Islands. It is the only modern lizard that has the ability to forage for food in the sea. When not swimming, it spends its days basking in the warm sunlight of the Galapagos rocks. Upon his journey to the islands, Charles Darwin first described the marine iguana population, calling them, “imps of darkness” for its appearance and black coloration. Other colors exist as well, and it is not unusual for bright green or teal-colored specimens to be seen on the island’s rocks.

The marine iguana finds nearly all of its food in the sea. It is very uncommon for the iguana to hunt or forage on land, because it prefers to eat seaweed and algae. It features a wide, flat snout along with sharp teeth that allow it to scrape algae off of sea rocks. Since this feeding process results in an excess of salt ingested by the reptile, it also has an unusual nasal gland that lets it filter out the salt, often resulting in patches of white salt lining its face.

As a cold-blooded creature, the marine iguana cannot spend a great deal of time in the cold waters foraging for food. After a diving session, it must bask on the warm rocks until it gets its internal temperature up to a more comfortable level. During this time, its exhibits sluggish movement and is highly vulnerable. Generally, the marine iguana moves in a clumsy manner on land because its physiognomy is designed to lend it graceful swimming abilities. When on land, these iguanas are highly defensive and will bite any potential nearby threat.

Just like the other animal species of the Galapagos Islands, the marine iguana is totally protected by the state of Ecuador. It is illegal to hunt, own, or otherwise disturb the marine iguana population of the islands in any way. They are considered, “vulnerable” by the IUCN because of introduced predators to the islands for which the iguanas have no natural defense. Occasional lack of food resulting from natural storms such as El Niño has drastically reduced the marine iguana population in the past, and conservation efforts continue to this day.

Hybrid Iguana

The aptly named hybrid iguana is the offspring of breeding between two closely related species of iguana: a male marine iguana, and a female land iguana. Both of these species are indigenous to the Galapagos Islands, and there is a small area in which their territories overlap. The hybrid iguana is a first-generation hybrid but does not seem capable of producing offspring. Because it inherits different specializations unique to the iguana parents, the hybrid iguana often has an easier time adapting to the environment offered by the Galapagos Islands where it lives.

Hybrid iguanas carry the sharp claws of their marine iguana parent, making them able to climb onto the Galapagos cacti and feed on them in a way that the land iguanas cannot. Despite having the powerful swimming tail of the marina iguana parent, the hybrid iguana prefers to hunt on land, and is rarely seen in the water. It prefers to use the sharp claws it has inherited to get food that is normally inaccessible to the land iguanas from which it claims half of its ancestry. This is one example of an ideal adaption for this hybrid species.

Normally, iguanas of these separate species do not mate, but certain environmental circumstances of the recent past have led to a proliferation of hybrid offspring. Of note is the 1997 El Niño storm season that raised the water temperatures enough to kill off a large amount of seaweed- a primary food source for the marine iguanas. This led the marine iguanas to seek more food on land, putting them in the same habitat as the land iguanas with whom they consequently mated. This produced a statistically significant number of hybrid iguanas that now populate the islands.

As a hybrid of two separate iguana species, the hybrid iguana shares characteristics of both and is generally assumed to look much like what the common ancestor of both its parents must have looked like. It retains the dark skin of its father, but often exhibits lighter bands of color that come from the mother. Its spinal crest is smaller than that of the marine iguana, but its head resembles the marine variety far more aptly than the terrestrial parent. The feet of the hybrid iguana are only slightly webbed.

Whale in Ocean