Turtle

Sea Turtle (Testudo mydas)
Turtles are reptiles of the order Testudines, known for their special bony or cartilaginous shell, which extends from their ribs and acts as a shield. The earliest known members of the group date back to 157 million years ago, making them one of the oldest reptile groups – older than snakes and crocodilians. Turtles are ectotherms, meaning that their internal temperature varies according to their environment.

Habitat

Turtles are found above and below ground. They can be found in all warm and temperate waters throughout the world and some migrate hundreds of miles between nesting and feeding grounds.

Size & Appearance

Known turtle species span in length from 3 inches to 6.6 feet and range in weights between 5 ounces to a full ton – 2,000 pounds! Turtles are separated into two groups depending on how they withdraw their necks into their shells. The Cryptodira withdraw their necks under their spines, while the Pleurodia contract their necks to the side. Turtles have rigid beaks and use their jaws to cut and chew food. The jaws are covered in sharp, horny ridges rather than teeth. Their upper shell is called the carapace while the lower shell is called the plastron. They are joined together on turtles’ sides by bony structures called bridges.

Diet

Turtles’ diets are largely dependent on the species of turtle and the habitat in which they are found. Typically, turtles’ diets consist of many plants that grow in water, small insects, snails, worms and even dead marine animals and fish. Due to the importance of protein intake in their growth, any wild turtles are mainly carnivorous when they are young and gradually add plants and vegetation to their diets as they age.

Fun Facts

Turtles are amniotes, meaning that they breathe air and lay eggs above ground.
The word turtle is used differently by region. In North America, all chelonians are called turtles, including tortoises and terrapins. In Great Britain, the word turtle is only used for sea-dwelling species.
The largest turtle ever known was Archelon ischyros, a Late Cretaceous sea turtle known to have been up to 15 feet.
Turtles stopped having teeth about 150-200 million years ago.