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Leatherback Turtles

The largest of all sea turtles, and one of the largest reptiles on earth, the leatherback turtle ranges in size from 4-8 feet in length (1.2 - 2.4 meters) and weighs between 500-2,000 pounds (225 - 900 kg). The average adult measures in between 5-6 feet (1.5 - 1.8 m) and weighs 600-800 pounds (270 - 360 kg).

Migration Routes (Evidence for thermoregulation)

Tracking research has shown that turtles follow migration routes across various oceans and habitats. They migrate to the nutrient rich, although very cold, Canada. Nesting grounds are commonly found throughout the Caribbean, in particular the tropical waters. Leatherback turtles are unique reptiles as they are able to cope with such a range of temperature conditions, unlike other reptiles that can only survive cold temperatures during the hibernating state. This led to the discovery of these massive reptiles ability to physically regulate their temperature.

How do they carry out Thermoregulation?

Due to their large size, leatherback sea turtles have a small surface area to volume ratio, therefore the core temperature of the turtle changes at a much slower rate; this is known as gigantothermy. When Leatherbacks are in cold waters, there is an increase in their flipper stroke frequency, leading to an increased heat production. Simultaneously the turtle’s circulatory system is decreasing blood flow to the extremities and storing heat in the core of the turtle through the use of a dense network of arteries and veins. As the blood flows through the arteries from the core of the turtle to its extremities, the blood’s heat is transferred to the blood flowing through the veins and back to the core. In addition, they are covered in a layer brown adipose tissue, which is an insulating layer of fat. This enables them to preserve more than 90% of heat at the core of the animal, reducing the heat loss due to the exposed extremities. When in high temperature waters, the opposite happens. Flipper stroke frequency decreases considerably, and blood moves to the extremities and expels heat through the areas not covered in the insulating tissue.