What is a Turtle or Tortoise?
Turtles and tortoises make up the order testudines which is further divided in to thirteen families. They are sometimes called chelonians as their taxonomic order is known as Chelonia which comes from the Greek word for tortoise.
Their defining feature is a large shell which sits on their back. The upper portion of the shell is known as the carapace while the lower portion is known as the plastron. They also all have 4 limbs and a toothless beak on their jaw. This shell is formed of bone and covered with scutes formed from keratin.
These animals are believed to be among the oldest of all the living reptiles. It is thought that they first appeared 200 million years ago.
The naming of the various types of turtles and tortoises has changed over time. Previously the land based species were called tortoises, the fresh water species were known as terrapins with the term turtle being use for marine species. These days most of the water going species are known as turtles while the land-based species remain as tortoises.
Turtles tend to have a more streamlined, flattened shell which helps them to move easier through the water and have flipper like legs and webbed feet to help them swim. Tortoises have domed shells and feet for walking on land.
Tortoises and turtles lack teeth using their sharp jaws to tear food.
The tortoises are extremely long-lived with some surviving for up to 150 years.
There are over 300 species of turtle and tortoise. The largest of these is the leatherback sea turtle which has a shell measuring up to 2.4m (8ft) long while the smallest is the speckled cape tortoise measuring just 7.9cm (3.1in) long.
Reptile Fact Files
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