The marine iguana is the only marine species of lizard in the world; it has changed its behavior, diet and physiology through natural selection during thousands of years.
There are seven subspecies, most of them developed in different islands. They have black bodies that sometimes especially during mating season and in different times on distinct islands, can have some colorful patches with green, orange, grey and yellow tones.
Marine Iguanas are ectothermic animals, same as all reptiles. As a result, they need to thermo regulate their activities in order to survive, by behavior. They need to warm up with the sun to the ideal temperature of 35.5C to successfully perform an activity such as feeding, or to even move from one place to another. Their actions are dependent on the water temperature and climate, for example entering the ocean to feed they can lose up to 10C (mainly in the night).
Marine Iguanas must constantly warm up in daylight by lying flat, in order maximize how much heat they are receiving, also marine iguanas need to cool off when the sun is too strong by avoiding direct rays on their body. These animals are capable to even slow down their metabolism and heartbeat, in order to optimize their energy consumption. Typically, marine iguanas feed once a day, but depending on their size and needs they can do it every two or three days.
Sexual maturity is reached after 8 years and they can lay between one to four eggs, breeding season is usually in the months of November and December.
Marine Iguanas can be seen on the majority of the Galapagos shoreline as they feed on algae that grow in all intertidal zones of the archipelago. They are able to feed on almost all kinds of seaweed with the exception of the brown one ( it makes them sick). They prefer shallow water or exposed sea weed in order to feed without the necessity of diving, thus saving body temperature. However, it needs to be clear that marine iguana can dive as deep as twelve meters and hold their breath for about one hour if needed.
Their flattened tails help them to swim efficiently. These iguanas have developed a special gland to secrete the salt they ingest by feeding, such gland is located by the ear and is connected to the nose rich from where they expel a salty solution. Such salty solution is expelled by sneezing.