Description and Diet
Sea turtles are reptiles that are very well-suited to aquatic life. One way this can be seen is in how they've been around for more than 100 million year, towards the end of the jurastic period. They are very similar now to how they were then as well. Sea turtles have a hydrodynamic shape, flipper like limbs, and a large size. They range from 2 - 6 feet. Their front flippers are long and powerful, and their back rear flippers are short. They move their flippers into a figure eight when they swim. Unlike terrestial turtles, sea turtles can't retract their heads into their shells. The leatherback sea turtle has a bony shell that is covered with a thick, leathery skin. The other six species (7 in total) all have hard shells. You can find turtles in tropical and subtropical waters around the world.Sea turtles are mostly carnivorous, although the green sea turtle is primarily herbivorous. It feeds on algae or marine grasses. The hawksbill and flatback sea turtle feed on invertebrates, and the others feed on crustaceans and mollusks.
Reproduction and Survival
Most sea turtles only go to shore for nesting. This happens roughly every three years. In the summer, the female will return to the same beach where she was born. Loggerhead sea turtles do this by remembering the unique magnetic field of the beach. This ability to navigate using magnetic field is not unlike a sailor using a compass. They will dig a nest with their rear flippers in the sand. She can lay from 80 to over 150 eggs at a time. Although nesting season happens only every few years, females may nest multiple times a nesting season. The sex of the turtles is determined by the average temperature of the nest. Higher temperatures around 88 degrees F or 31 degrees C will make more female babies. Lower temperatures around 82 degrees F or 28 degrees C make more male babies. The eggs roost for about two months. When they hatch, they can fit into the palm of a hand. Sea turtles grow slowly but steadily, and in a year, those babies can grow to the size of a dinner plate. Sea turtles live for multiple decades.Sea turtles have have to overcome great odds to make it to adulthood. When the nest of around 100 eggs is layed, 20% of them won't hatch. Of those that hatched, 50% will make it from their nest to the ocean. They have to avoid crabs, raccoons, gulls, and other predators to make it to the ocean. When they make it there, 50% of the baby sea turtles will die within their next several months. They must avoid new prdators and getting overwhelmed by the turbulent ocean. As they grow up, there a fewer and fewer predators. In around 20 years, when those babies are ready to lay eggs, less than 10% of the orgiinal babies will be alive.