Hobbies And Interests
Adaptations
Marine iguanas have a nasal gland connected to the nostrils that excretes excess salt. This adaptation lets them live in salt water. When the iguana "sneezes," excess salt is expelled from the body into the air. The salt accumulates on their faces, lightening their features so it looks like they're wearing a white "wig."
Appearance
The species varies in size and color. The smallest are found on Genovesa island and the largest are found on Fernandina and Isabela islands, according to the MarineBio website. Marine iguanas range in color from dark gray to black. During mating season, the males develop red or green patches on their backs from eating seaweed available at that time.
Breeding
Breeding season runs from December through March, and nesting season runs from January through April. Females dig burrows in the sand and lay between one to six eggs. They guard the burrow for several days before leaving the eggs to incubate for 89 to 120 days. Upon hatching, the young weigh between 50 and 60 g. They immediately seek cover.
Conservation
Marine iguanas are protected by Ecuadoran national legislation. However, the population is under threat because of pollution and invasive animal species. No one knows how many remain. The IUCN Red List of Threatened Species lists the species as vulnerable, while the Convention on International Trade in Endangered Species of Wild Fauna and Flora lists them as "nearly threatened with extinction."
Feeding
Marine iguanas are herbivores and feed on algae growing on rocks near the shore. When feeding, they remain submerged for up to an hour, although dive times of 5 to 10 minutes are common. They are cold-blooded and quickly lose body heat in the cold ocean water. To restore their body temperature, you will see them basking on rocks for long periods. Their dark color helps them absorb heat.
Mating
Females reach sexual maturity between 3 to 5 years of age; males between 6 to 8 years old. Males have "harems" of several females. Males defend their territory from other males and use "head bobbing" to warn others to stay clear. Occasional fights break out between males and the two males will put their heads together and attempt to push the other away.
Predators
Marine iguanas have few natural predators. Known predators include crabs, hawks, owls and snakes. However, humans have brought cats, dogs and rats to the archipelago. The iguanas have few defenses against these invading species. As a result, the population is in decline on many islands.