Turtle

Turtles are reptiles in the order Testudines, characterized by a bony shell that forms part of the body.

Turtles are reptiles in the order Testudines, characterized by a bony shell that forms part of the body. The group includes turtles, tortoises, and terrapins, and species live on land, in freshwater, and in marine environments. Turtles are among the oldest living reptile lineages, with hundreds of extant species worldwide.

Classification and anatomy

Turtles are reptiles in the order Testudines. They have a bony shell that is an integral part of the skeleton and body, formed largely from the ribs and other skeletal elements. Most species have toothless jaws with a horny beak, and many can retract the head and limbs into the shell, though not all can do so fully.

Diversity and habitat

Living turtles occur in a wide range of habitats, including terrestrial, freshwater, and marine ecosystems. They are distributed across most of the world, with Antarctica as the major exception. More than 350 living species are recognized, ranging from tortoises on land to sea turtles and many freshwater species.

Life history

Turtles lay their eggs on land, even when the adults live in water. Temperature can influence offspring sex in many species, and lifespans vary widely, with some species living for more than a century. The diet of turtles varies by species and can be herbivorous, omnivorous, or carnivorous.

Evolution

Turtles are regarded as one of the oldest surviving reptile lineages. Fossil evidence indicates an ancient origin dating back to the Triassic period, with turtles having existed for roughly 200 million years or more.

Turtles in Canada

Canada is home to several native turtle species, including freshwater turtles and the endangered leatherback sea turtle in Atlantic waters.