Author: Qiao Yilun
This article is from the magazine Knowledge is Power
The king of the big stomach
The main diet of leatherback turtles is jellyfish, but also some anthocysts and molluscs. They are the king of the stomach and can consume the equivalent of 70% of their body weight every day.
We know that turtles have no teeth, and they rely on the cut surface of the upper and lower jaws in the mouth to cut and swallow food. However, the leatherback turtle's mouth is covered with many jagged stalactite-like "teeth". This kind of sharp "teeth" can make the jellyfish in the mouth not slip, which also means that for a variety of jellyfish of different sizes, the leatherback turtle can come without refusal and eat them all. In addition, the esophagus of the leatherback turtle is very long, extending from the stomach to the tail and then to the stomach. So the entire esophagus is like a conveyor belt, constantly transporting, storing and digesting food.
A huge body that stands out from the crowd
Leatherback turtles are unique in taxonomy, as a single family and a single genus. Compared to other turtles and tortoises, leatherback turtles are very different in body structure. Its carapace is not a bone plate and shield structure, but is replaced by a specialized leathery skin structure. In addition, this leathery skin is not as smooth as other turtle shells, but has 7 obvious longitudinal ridges, which is the origin of the name "leather turtle".
Leatherback turtles have the most hydrodynamic shape of any marine turtle, with a bluish-black body and dotted with off-white spots. Females have a pink hue on the top of their heads and throats and are larger than males. Their limbs are flattened like oars and have only a vestige of a degenerate toe. The ratio of the forelimbs to the body of leatherback turtles is the largest of all sea turtles, which provides a powerful tool for them to paddle and swim. Turtles are known for their slow speed, but leatherback turtles swim very flexibly and quickly in the water, like "flying", and can reach speeds of up to 35 kilometers per hour!
The secret to breathing in the water
Turtles are reptiles that breathe with their lungs, but about 70% of the living turtle species live in aquatic habitat, and the leatherback turtle is a turtle species with strong aquatic habits. They spend almost all of their lives in the sea, and only the females need to go ashore when laying their eggs. Leatherback turtles live in the ocean for a long time, what other ways to breathe in addition to breathing with their lungs?
Obviously, for highly aquatic turtles such as leatherback turtles, the lungs are not their only respiratory organs. The mucous membranes of the inner wall of their oropharyngeal cavity have a microvascular system that can exchange gases, and the thin-walled sacs in the cloaca can also breathe. Even in low oxygenated water, leatherback turtles do not get choked to death, sinking on the ocean floor for 20 hours. In addition, the shoulders of leatherback turtles have a special countercurrent heat exchange blood supply system, coupled with the barrier of the fat layer, so that they can dive into the deep sea of 1000 meters. This depth exceeds the physiological limits of all other reptiles. Like diving mammals such as sperm whales, leatherback turtles have adapted to the low temperatures and enormous pressures of the diving area.
The turtle has been found in all tropical and temperate oceans of the world, and has been documented in cold polar waters, mainly in the warm waters of the Atlantic, Indian and Pacific Oceans, and the breeding grounds are basically located between 30° north latitude and 20° south latitude.