The Largest Tortoise Species, a Cold-Blooded Reptile – Pancake Tortoise

Sept. 29, 2025, 1:50 a.m. Pets

The order Testudines is a very ancient and prosperous order within the reptile class. The fossil records of its ancestors date back to 2.2 million years ago, discovered in Guizhou, China, featuring the half-shelled turtle. Testudines originated earlier than Crocodilia and Squamata, having survived several mass extinction events, and currently consists of 14 families and about 350 species. Except for high-altitude, high-latitude, and extremely arid regions, they are found almost everywhere in the tropical and temperate regions of the world, representing a very common animal group.

Left is the Necked Turtle Suborder, and right is the Side-Necked Turtle Suborder.

Testudines is divided into two suborders: the Necked Turtle Suborder and the Side-Necked Turtle Suborder.The Necked Turtle Suborder retracts its head into the shell when it is retracted, and the neck is curved; the Side-Necked Turtle Suborder extends its head outside the shell. However, within the Necked Turtle, some species cannot retract their heads into the shell, such as the Hawksbill Turtle and Leatherback Turtle.

According to their habits, Testudines can be roughly divided into Freshwater Turtles, Terrestrial Turtles, and Semi-Aquatic Turtles.

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According to the hardness of their shells, Testudines are generally referred to as Turtles (hard shell) and Softshell Turtles (soft shell).

However, there is one Turtle that is very special, it has no hard shell, but it is not like Turtles and Softshell Turtles, and it also lives in the ocean, that is the Leatherback Turtle (Leatherback Turtle). It is currently the largest Turtle in Testudines.Leatherback Turtle Overview.

There are currently 7 species of sea turtles, namely Olive Ridley Turtle, Kemp's Ridley Turtle, Flatback Turtle, Hawksbill Turtle, Green Turtle, Loggerhead Turtle, and Leatherback Turtle. The first 6 species belong to the Sea Turtle family, only the Leatherback Turtle belongs to the independent Leatherback Turtle family. The Leatherback Turtle’s appearance is very different from other 6 sea turtles.

Leatherback Turtle vs. Other 6 Sea Turtles Comparison Chart.

Sea Turtle family 6 kinds of turtles' shell is oval or nearly circular, the shell has 3 rows of horn-like shields, the shields under the shields are formed by excessive growth of ribs, vertebrae, and the space between ribs, forming a very hard shell. The shell color is brown, reddish-brown, olive green, orange-yellow, or gray, with vibrant colors.

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In contrast, the Leatherback Turtle's appearance is much more rustic, with dark black or dark blue color, scattered with white spots. The back is a thin and tough cenuaceous, below the cenaceous has a thick brown fat tissue, this is a specialized heat-generating tissue, which is equivalent to a heat blanket, it can also maintain the body temperature of the Leatherback Turtle in cold water.

The third method is the exchange of blood temperature system.Through these three methods, the Leatherback Turtle can enter sea areas with high latitudes and deep waters, and it has created several biological miracles.

John Grady’s research in the 2014 issue of the journal *Science* shows that the growth rate of dinosaurs ranges from 4.8-16, which is ahead of most reptiles and fish, but not as much as most mammals.However, this paper was disputed by M. D. D’Emic one year later, claiming that John Grady’s calculation of the growth rate of dinosaurs was incorrect.The Leatherback Turtle’s survival situation.Globally, the number of Leatherback Turtles has decreased by 40% in the past 30 years, and the number of Leatherback Turtles in the Pacific Ocean has decreased by 80% in the past century.International efforts are underway to increase the population of Leatherback Turtles.Based on the recent number of Leatherback Turtle eggs and hatchlings, the trend of declining Leatherback Turtle population is being controlled, predicting that the population will increase around 2030, assuming that international protection of Leatherback Turtles is not relaxed.