There are a total of about 250 species of turtles grouped into 9 families. They are found only in the temperate or tropical zones. Turtles are mostly adapted to a freshwater or terrestrial habitat, and a small group to sea life. Turtles are carnivorous or herbivorous. All species lay eggs, which they bury in holes. Turtles and tortoises are generally long-lived; some species live for more than 100 years.