Sea turtles of the family Cheloniidae represent a wide spread group of turtles that occur in virtually all of the world's temperate and tropical seas.  Throughout the world, five genera and six species are known to exist.  In Texas, four different species have been found in the Gulf coast and on its shores.  These large turtles have a carapace covered in keratinized scutes and depending upon the species can range in size from 30 inches (100 cm) to 39 inches (124 cm) and weight as much as 95 pounds (43 kg) to 400 pounds (200 kg).

     Sea turtles are highly specialized for an aquatic life in a marine environment.  The most noticeable difference between sea turtles and most other turtles are the fore and hind limbs which have been modified into flippers.  The physiology of these reptiles is also of interest as sea turtles must effectively regulate the amount of salt taken into their bodies.  Salt secretion glands located near the corner of the eye help rid the body of excess salts.

     Males rarely, if ever leave the water.  Coming ashore is mostly a task reserved for the females as they continue the millennia old ritual of females returning to the same nesting beaches that they hatched from themselves.  Depending upon the species, females can lay 50-160 leathery round eggs.  Females come to shore under the cover of darkness to lay their eggs 

Sea turtles are facing  imminent  extinction due to man made pressures ranging from pollution, incidental deaths from the fishing industries and the direct take of eggs and slaughter of adults for food.  
The Loggerhead sea turtle (Caretta caretta)

The Green sea turtle (Chelonia mydas)

Hawksbill sea turtle (Eretmochelys imbricata)

Atlantic Ridley (Lepidochelys kempii)