On Earth, there are 343 turtle species classified into three groups: land turtles, aquatic turtles and sea turtles. Although the three reptiles belong to the same family (chelonians), their habitats are different and turtles have adapted by developing morphological characteristics allowing a better survival. A large part of turtle species is now endangered, including the species living in French Polynesia.
Here are some facts:
Land turtles have a longer lifespan than aquatic and sea turtles. Turtle longevity record is held by the giant Seychelles and Galapagos land turtles who can reach 150 years.
Land turtles can retract their legs and head inside their shell. Their shell is mostly dome-shaped and heavy, which prevents predators attacks.
Aquatic turtles have webbed legs. They have a carapace usually less dome-shaped that land turtles.
The shell of sea turtles is light, flat and streamlined. These characteristics allow it to slide better underwater.
Sea turtles only come back to land to lay their eggs.
A large portion of these species are currently threatened, including Polynesian sea turtles.