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The Leatherback Turtle, Part 1

Growing to a length of up to six and a half feet, about the length of a Volkswagen bug, and weighing in at as much as fourteen hundred pounds, the Leatherback is the largest sea turtle on earth. Leatherbacks can be found in various parts of the world, laying their eggs on tropical beaches off the Atlantic, Pacific, and Indian Oceans.

Unlike other sea turtles, the Leatherback can survive in cold waters. A thick, oily layer of fat under their skin helps insulate them so that their body temperature remains warmer than the water around them. Also they're large in size, have high metabolisms, and are able to temporarily turn off the blood flow to cold flippers, keeping their blood warm.

But more interesting perhaps is the role temperature plays in the outcome of the sex of the hatchlings of not just Leatherback turtles, but all sea turtles. Females lay an average of one hundred eggs at a time, burying them in pits in the sand. The incubation temperature not only determines whether any of the eggs survive in the first place, but also directly determines the outcome of the sex of the turtles.

At about eighty-five degrees Fahrenheit, roughly half the hatchlings will be male, half female. If the temperature is slightly under eighty-five, most, if not all, the hatchlings will be male. If above eighty-five, most or all of the hatchlings will be female. Prolonged exposure to a temperature ninety-five degrees and higher or seventy-seven and lower, though, and the eggs will not survive.

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