Sea Turtles: Diving Deep and Living 100+ Years

Sea turtles are large reptiles that have lived in the Earth’s oceans for more than 100 million years. They existed alongside dinosaurs and have changed very little since then. There are seven species of sea turtles, including the Green, Loggerhead, and the giant Leatherback. These animals are found in warm and temperate waters around the world.

Shells and Flippers

Unlike land turtles, sea turtles cannot pull their heads and legs inside their shells for protection. Their bodies are streamlined for swimming. They have large, strong front flippers that propel them through the water and smaller back flippers used for steering.

The top part of the shell is called the carapace, and the bottom is the plastron. Most sea turtles have hard, bony shells covered in large scales called scutes. The Leatherback is the exception; instead of a hard shell, it has tough, rubbery skin reinforced by tiny bones.

Breathing and Diving

Although sea turtles live underwater, they breathe air and must come to the surface. When they are swimming actively, they surface every few minutes. However, they are experts at holding their breath. When resting or sleeping, a sea turtle can stay underwater for several hours. During these deep dives, their heart rate slows down dramatically to save oxygen. Leatherback turtles can dive more than 3,000 feet (900 meters) deep in search of jellyfish.

Nesting and Life Cycle

Sea turtles spend almost their entire lives in the ocean, but females must return to land to lay eggs. Remarkably, a female turtle returns to the exact same beach where she hatched, known as her natal beach. She crawls onto the sand at night, digs a hole with her back flippers, and lays a clutch of soft, leathery eggs.

After about two months, the babies hatch and dig their way out of the sand. They instinctively scramble toward the brightest horizon, which is usually the reflection of the moon and stars on the ocean. Sea turtles grow slowly and live very long lives. Many species can live to be 80 to 100 years old.