Marine Reptiles

Although reptiles are the most ancient, truly terrestrial vertebrates, they have also evolved marine species several times during their 300 million-year history; the turtles are the oldest group of living reptiles in the sea, though there are only eight truly marine species left.

Sea turtles spend most of their lives in the water, coming ashore only to lay eggs. Sea snakes are relatively recent retunes to the sea but, nevertheless, they are the most abundant living marine reptiles both in terms of numbers and variety of species. Although they are all highly venomous carnivores, related to cobras, sea snakes are not aggressive to humans.

The size of their mouths, in which the fangs are placed to the rear, makes it difficult to be bitten. Lizards and crocodiles are represented by only two species, the marine iguanas and the saltwater crocodiles. The main natural limitation on the distribution of reptiles is water temperature; they are cold blooded and cannot survive for any length of time in cold water.

Saltwater crocodiles pose a danger to humans and are more feared than sharks in some parts of the world. Attacks are relatively rare, however, with 14 deaths being recorded in Australia between 1976 and 2003. The crocodile’s reputation for attacking humans and the demand for its skin increased hunting, causing a serious decline in the wild populations. However, since the 1970s, protective measures in Australia have saved these crocodiles from extinction.