Consist of 331 species – turtles, freshwater turtles, tortoises, terrapins and sea turtles – throughout the world.
The only place where turtles are can’t live is Antarctica.
They are only vertebrates on Earth whose arms connect to their body.
The most freshwater turtles are temperature-dependent sex determinant. High temperature produce female, while low temperature produce male.
Turtles have been on the earth for more than 200 million years. They evolved before mammals, birds, crocodiles, snakes, and even lizards. Turtles are one of the oldest and most primitive groups of reptiles and have outlived many other species. One can only wonder if their unique shell is responsible for their longevity. But, a newest study shows that they are not too primitive and more related to bird.
The earliest turtles had teeth and could not retract their heads, but other than this, modern turtles are very similar to their original ancestors.
Several species of turtles can live over a hundred years of age, for example Aldabra tortoise. A documented case of longevity involves an adult Indian Ocean Giant Tortoise that, when captured as an adult, was estimated to be fifty years old. It then lived another 152 years in captivity.
Turtles have good eyesight and an excellent sense of smell. Hearing and sense of touch are both good and even the shell contains nerve endings.
Some aquatic turtles can absorb oxygen through the skin on their neck and cloacal areas allowing them to remain submerged underwater for extended periods of time and enabling them to hibernate underwater. All turtles can go without oxygen for several hours, but the western painted turtle can go without oxygen for 30 hours at room temperature and four months at 37 degrees Fahrenheit.
Turtles will live in almost any climate warm enough to allow them to complete their breeding cycle.
Most freshwater turtles do not tolerate the cold well, but the Blanding’s turtle has been observed swimming under the ice in the Great Lakes region.
Turtles range in size from the 4-inch such as Bog Turtle to the 1500-pound such as Leatherback turtle (a species of sea turtle). The biggest freshwater turtle ever found is Rafetus swinhoei in Vietnam.
North America, China and Indonesia have a large variety of turtle species, but Europe contains only two species of turtle and three species of tortoise.
The top domed part of a turtle’s shell is called the carapace, and the bottom underlying part is called the plastron.
The shell of a turtle is made up of 60 different bones all connected together.
The bony portion of the shell is covered with plates (scutes) that are derivatives of skin and offer additional strength and protection.
Most land tortoises have high, domed carapaces that offer protection from the snapping jaws of terrestrial predators. Aquatic turtles tend to have flatter, more aerodynamically shaped shells.
A species of freshwater turtles Red Eared Slider is the most invasive species in the world.