Characteristics
The smallest and most endangered sea turtle species is Kemp's ridley, scientifically known as Lepidochelys kempii. A normal adult Kemp's ridley has a carapace length of 60–70 cm (24–28 in). both top shell, or carapace, is heart-shaped and very large, giving them a strong and sleek profile that works well for both pelagic and coastal lives. They mostly graze in the shallow coastal waters, where their compact form helps them navigate.
The Kemp's ridley sea turtle is easily identifiable by its unusual coloring. A juvenile's plastron and carapace have a deep purple or almost black color. The plastron becomes a light yellow as they develop, and the carapace takes on a more subdued gray-olive hue. Because of their different habitats, which range from the wide ocean to coastal shallows, their pigmentation serves as a camouflage mechanism.
Unlike the majority of sea turtle species, Kemp's ridley only has five pairs of costal scutes—the big scales on the carapace. Their smooth, spherical shells are partially due to the decrease in the number of scutes. When turtles are young, their carapaces have serrated edges, but as they mature, these edges usually flatten out. A higher domed carapace compared to other species is another distinguishing feature of Kemp's ridleys.
Sea turtles of the Kemp's ridley species are identifiable by their moderately sized, noticeably triangular heads that include a small beak. Because they feed mostly on benthic crustaceans, such as crabs and mollusks, these animals have strong jaws. Their beak-like mouth anatomy allows them to rip their food to shreds, a feeding specialty that serves them well in their coastal habitat.
Like other marine turtles, Kemp's ridley rely on their flippers to propel themselves around. They propel themselves powerfully through the water with their well-developed front flippers, which resemble paddles. Shorter and more rounded, the back flippers help with steering and navigating. The arrangement of their flippers gives them the ability to swim with great agility, allowing them to escape predators or catch prey with sudden bursts of speed.
The size variation among Kemp's ridley sea turtles during their life cycles is another distinctive physical trait. Little hatchlings weigh only around 15 to 20 grams (0.5 to 0.7 ounces) and have a carapace length of about 4 to 5 centimeters (1.5 to 2 inches). Their little stature leaves them open to a variety of predators, but as they mature, their bulk and tough exoskeletons provide them with better defenses.
Another distinctive reproductive trait of Kemp's ridley sea turtles is TSD, or temperature-dependent sex determination. How hot or cold the sand becomes while the eggs are incubating determines the gender of the offspring. In general, girls are born when temperatures are warmer and boys when temperatures are lower. This trait is present in all species of sea turtles and has important consequences for the dynamics of their populations, particularly in light of the fact that nesting beaches' temperature profiles might fluctuate due to climate change.