Did you know that the largest turtle ever, Archelon, was the size of a small truck? Scientists believe it must have weighed four or five tonnes. The long-extinct Archelon was a member of what was once a hugely diverse family. There used to be dozens of turtle species but now they are down to as few as seven. Some scientists maintain there is an eighth species which lives in the eastern Pacific, but most believe that it is a small genetic variation of the green turtle.

Sea turtles are found throughout the waters of all tropical countries. They like to stay near warmer waters because they are cold-blooded – that is, their body temperature is regulated by external conditions, unlike humans, whose bodies self-regulate internal temperatures no matter how hot or cold it is outside.

For this reason turtles are rarely found in extremely high or low latitudes – except for the leatherback, which has a greater layer of fat and hunts jellyfish in colder waters. They can range as far north as Canada and as far south as South Africa and Argentina, whereas their hard-shelled cousins prefer to stay much closer to the tropics.

Want to learn more...?

Visit the ARKive website to find out more about the biology and life history of all species of turtles. There are also some cool photos and videos to look through. Just click here.