What Marine Iguanas Eat

Marine iguanas (Amblyrhynchus cristatus) are found in the Galapagos Islands. Their relative, the land iguana, also inhabits the Galapagos Islands -- however, the marine iguana is unique among all lizards as it is the only species that is sea-going. This herbivore's diet is quite limited and they search for food in the sea. Marine iguanas cannot regulate their own body temperature, so in order to feed in the cold waters, they must lay in the sun until their body temperatures raises to 36 degrees Celsius.

  1. Marine Algae

    • Marine iguanas feed on nine species of marine algae (seaweed). These are Ptersosiphonia paucicorticata, Blossevillea galapagensis, Tylotus ecuadorianus, Loposiponia villum, Bryopsis indica triseriata, Gelidium, Priontis abbreviata, Plocamium pacificum and Glossophore galapagensis. The marine iguana searches for marine algae under the water and scrapes it from rocks using its razor-sharp teeth.

    Emergency Food

    • Marine iguanas usually feed solely on marine algae. However, there are substitutes. One example of such a treacherous time was the El Nino trade winds of 1983. The marine algae that the iguanas were so dependent on was quickly wiped out, resulting in the death of 50 percent of the marine iguana population. Other disasters such as water pollution and oil spills also threaten the ecosystem in which marine iguanas live and the continuity of their food source. In times of need, the marine iguanas resort to eating foods such as succulent plants and cacti growing on land near the shore. It has also been reported they will eat grasshoppers and crustaceans.

    Salt Water

    • Marine iguanas almost entirely fill their stomachs with salt water when they are diving for food. The iguanas must not retain this salt, so they blow it out through nasal glands positioned between their eyes and nostrils. Marine iguanas' heads will often have a white appearance -- this is a result of their salt-blowing technique and the resulting residue. Marine iguanas do not drink fresh water, instead they retain the water they need from the salt water ingested.

    Vitamins

    • Vitamin D3 and calcium are important to the marine iguana. A deficiency of these can cause a swollen lower jaw and, consequently, difficulty eating. In this instance, fractures can easily occur. Vitamin B1 is also important or paralysis of the back legs may result. Marine algae provides all of the vitamins and minerals that a marine iguana needs; hence, shortages of this prove detrimental for the species.