Turtles are on of the oldest and most primitive groups of reptiles, and have been on Earth for more than 200 million years, evolving even before mammals, birds, crocodiles, snakes, and lizards! Dinosaurs went extinct 65 million years ago, yet turtles are still here! The early turtle ancestors had teeth and could not retract their heads, unlike their modern family. Today, several species of turtles can live to be over 100 years old, and range in size from 4 inches to 1500 pounds! Even being on Earth this long, many turtle species are listed as threatened, endangered, or critically endangered. Some species are estimated to be extinct in 45 years.