The earliest known sea turtle fossils are about 150 million years old. It is theorized that some species can live over 100 years. There is no way to determine the age of a sea turtle from its physical appearance. They grow slowly and take between 15 and 50 years to reach reproductive maturity, depending on the species. Once turtles reach dinner-plate size, they appear at feeding grounds in nearshore waters. It is theorized that they spend their earliest, most vulnerable years floating around the sea in giant beds of sargasso weeds, where they do little more than eat and grow. Researchers do not yet know how long baby turtles spend in the open sea, or exactly where they go. A female will not nest in consecutive years, typically skipping one or two years before returning. Most females nest at least twice during each mating season some may nest up to ten times in a season. In the U.S., nesting occurs from April through October. Nesting seasons occur at different times around the world. Most females return to nest on the beach where they were born (natal beach). Only females come ashore to nest males rarely return to land after crawling into the sea as hatchlings. Millions of sea turtles once roamed the earth’s oceans, but now only a fraction remain. Unfortunately, the spiritual significance of sea turtles has not saved them from being exploited for both food and for profit.
In the Miskito Cays off the eastern coast of Nicaragua, the story of a kind “Turtle Mother,” still lingers.
Sea turtles have long fascinated people and have figured prominently in the mythology and folklore of many cultures. After decades of studying sea turtles, much has been learned. Thousands of sea turtles around the world have been tagged to help collect information about their growth rates, reproductive cycles and migration routes. Most of this research has been focused on nesting females and hatchlings emerging from the nest, largely because they are the easiest to find and study. Research on marine turtles has uncovered many facts about these ancient creatures. However, sea turtles maintain close ties to land.įemales must come ashore to lay their eggs in the sand therefore, all sea turtles begin their lives as tiny hatchlings on land. Their streamlined bodies and large flippers make them remarkably adapted to life at sea. Their vision underwater is good, but they are nearsighted out of water. They hear best at low frequencies, and their sense of smell is excellent.
They do not have visible ears but have eardrums covered by skin.
Sea turtles do not have teeth, but their jaws have modified “beaks” suited to their particular diet. The olive ridley is usually less than 100 pounds, while the leatherback typically ranges from 650 to 1,300 pounds! The upper shell, or carapace, of each sea turtle species ranges in length, color, shape and arrangement of scales. Sea turtles come in many different sizes, shapes and colors. Hard scales (or scutes) cover all but the leatherback, and the number and arrangement of these scutes can be used to determine the species. Their shells consist of an upper part (carapace) and a lower section (plastron). Sea turtles are large, air-breathing reptiles that inhabit tropical and subtropical seas throughout the world.
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