A group of turtles is called a bale. Turtles have been in existence for over 200 million years and are the only reptiles with shells; they also do not have teeth.

The size of turtles varies greatly; the smallest ones measure only 3 inches long, while the largest turtle can grow over 6 feet. The majority of turtle species continue to grow throughout their life span; some species can live to be over 100 years old. The efficiency and operation of turtles' organs do not weaken in the turtle life cycle. The organs of a very old turtle look the same as organs of an immature turtle.