The Astonishing Size Of Fully Grown Sea Turtles

Sea turtles come in a variety of sizes, with the smallest being about the size of a dinner plate, and the largest, the leatherback, reaching sizes comparable to a golf cart. The leatherback sea turtle is the largest among all turtle species, with a carapace length of 6 to 9 feet. The largest leatherback sea turtle ever recorded was almost 10 feet long, weighing nearly 2,000 pounds. These turtles are unique in that they lack a hard shell, instead having a firm, rubbery skin. They are also the only sea turtles capable of maintaining a warm body temperature in cold water.

The leatherback is the largest sea turtle species

Leatherback sea turtles are easily distinguished from other species by their lack of a hard shell or scales. Instead, they are covered with a firm, rubbery skin, strengthened by thousands of tiny bone plates, giving them a "leathery" appearance. Their carapaces are large, elongated, and flexible, with seven distinct ridges running the length of their bodies.

Leatherback sea turtles have a wide range, found in the tropical and temperate waters of the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea. They have been spotted as far north as Canada and Norway, and as far south as New Zealand, South America, and the southern tip of Africa.

Leatherback sea turtles are the only sea turtles that feed almost exclusively on jellyfish. Their delicate, scissor-like jaws would be damaged by anything else. This diet poses a threat to their survival, as they often mistake plastic bags and balloons floating in the water for jellyfish. Some individuals have been found with almost 11 pounds of plastic in their stomachs.

The leatherback sea turtle population is declining in many parts of the world, and they are listed as endangered. Primary threats to the turtles include commercial fisheries, marine pollution, egg harvesting, and boat strikes.

Sea turtles are bigger than most other aquatic turtles

The leatherback sea turtle is also the heaviest, being the fourth heaviest reptile in the world. This is partly due to their unique shell, which is not hard like other turtles but instead composed of a layer of thin, tough, rubbery skin, strengthened by thousands of tiny bone plates. This gives the shell a leathery look, hence the name "leatherback".

The second-largest sea turtle species is the green sea turtle, which grows to a maximum length of 5 feet (152 cm) and a weight of 871 pounds (395 kg). The smallest sea turtle species is the Kemp's Ridley sea turtle, which grows to between 20 and 29 inches in length.

Sea turtles come in many different sizes, with the smallest being about the size of a dinner plate. The largest sea turtles, the leatherbacks, can reach sizes similar to a golf cart. However, these modern-day turtles are dwarfed by ancient sea turtles. Archelon, a giant sea turtle that lived during the Cretaceous Period, grew to sizes of roughly 13 feet in length.

The average size of a fully grown sea turtle

The size of a fully grown sea turtle varies depending on the species. The leatherback sea turtle is the largest of all the marine turtles. A fully grown leatherback has a carapace length of about 5 to 6.5 feet, with the largest leatherback ever recorded measuring 10 feet or 305 centimetres in length. They can weigh anywhere from 550 to 2,000 pounds.

The green sea turtle is the largest of the Cheloniidae family. An adult green sea turtle typically grows to between 3 and 4 feet in carapace length, with the largest ever found measuring 5 feet long. They weigh between 240 and 420 pounds.

The loggerhead sea turtle typically grows to around 3 feet long. The largest ever recorded was around 7 feet long.

The flatback sea turtle typically grows to around 3 feet long. Female flatbacks are usually larger than males.

The Kemp's Ridley sea turtle is the smallest of the marine turtles, growing to between 20 and 29 inches long.

The olive ridley sea turtle is one of the smallest marine turtle species. Males and females grow to roughly the same size, reaching on average over 2 feet long as adults.

The hawksbill sea turtle is found in both short to medium sizes. Males are usually shorter than females.

Overall, the average size range of a fully grown sea turtle is between 2.5 and 4 feet. An adult marine turtle can be below this limit or as big as 6.5 feet depending on the species.

The leatherback's unique shell

The leatherback sea turtle is the largest of all living turtles and the heaviest non-crocodilian reptile. It is easily distinguished from other sea turtles by its lack of a hard shell. Instead, its carapace is covered by oily flesh and flexible, rubbery skin, for which it is named.

The leatherback's shell, or carapace, is highly specialised for diving to extreme depths of up to 4,000 feet (1,219 metres). It has a smooth, leathery skin that covers a flexible matrix of bone. This unique design enables the turtle to withstand high hydrostatic pressures as it dives. The carapace is dark grey or black with white or pale spots, and has seven distinct ridges running the length of the animal.

The leatherback's shell is also well-adapted to thermoregulation, allowing the turtle to maintain its core body temperature in extremely cold water. This is due to a unique thermoregulatory adaptation that enables leatherbacks to withstand temperatures 18°C (32°F) colder than the surrounding water.

The leatherback's shell is distinct from other sea turtles in another way: it is scaleless. Instead of scutes, it has thick, leathery skin with embedded minuscule osteoderms. These osteoderms are made of bone-like hydroxyapatite/collagen tissue and have jagged edges, referred to as teeth. The osteoderms are connected by a configuration of interpenetrating extremities called sutures that provide flexibility to the carapace, enabling in-plane and out-of-plane movement between osteoderms. This flexibility is important as the carapace expands when taking in air and contracts when diving to great depths.

The leatherback sea turtle's shell is not just unique, it is also critical to its survival.

Ancient sea turtles were bigger than modern-day turtles

Sea turtles come in many different sizes, with the smallest being about the size of a dinner plate and the largest, the leatherback, reaching sizes similar to a golf cart. However, these modern-day turtles pale in comparison to ancient sea turtles.

Archelon, a giant sea turtle that lived roughly 80 to 66 million years ago during the Cretaceous Period, is one of the largest sea turtles ever to live on our planet. It grew to sizes of roughly 13 feet in length, and some sources even claim it may have stretched beyond 15 feet. To put that into perspective, the leatherback sea turtle, the largest living sea turtle species, typically grows to a length of 6 to 9 feet and weighs between 550 and 2,000 pounds.

Another giant ancient sea turtle was Protostega gigas, which swam in the inland sea that crossed North America during the Cretaceous. Some specimens exceeded 12 feet in length and weighed more than 2,000 pounds. Leviathanochelys aenigmatica, discovered in the southern Pyrenees in Spain, is also believed to have been similar in size to Archelon, making it one of the largest marine turtles ever.

The ancient sea turtles' enormous size likely helped them survive against fierce Cretaceous predators. Their hard shells offered some protection, but even these thick shells were not always enough, as evidenced by fossil specimens with shark teeth embedded in them.

The ancient sea turtles' sheer size puts them in a league of their own compared to modern-day turtles. Their massive bodies and long necks, combined with their powerful swimming abilities, made them formidable creatures in the ancient oceans.

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