There are about 250 species of turtles and tortoises, ranging from the tiny three-inch bog turtle of eastern North America to the seven-foot-long, one-ton leatherback sea turtle of the Atlantic and Pacific oceans. There are freshwater turtles, sea turtles who live in oceans, and tortoises—turtles that live on land.
All turtles have shells and scaly skin, but each species has special characteristics to live in its environment, such as webbed feet for swimming, long claws for digging, or a flattened shell to hide from predators in rock crevices.
Many tortoises who live in hot, dry climates stay in burrows during the heat of the day. This is because turtles and tortoises, like all reptiles, are "cold-blooded"—they are only able to regulate their body temperature by moving into cooler or warmer places. Such animals will die or become ill if forced to stay at temperatures outside of the range needed for normal body functions.
No matter where turtles live, they lay their eggs on land. Many turtles lay only a few eggs each year, and some lay only one egg every other year. In addition, many turtles reach sexual maturity at ten or more years.
Together, these factors mean that the birth rate of wild turtle populations is very low. For many reasons, the collection of wild turtles places tremendous pressure on populations and has caused the endangerment of many species, especially when species face other human-caused threats like habitat destruction, water pollution, and unnatural predators.
Updated May 31, 2007.
