American Oceans
Leatherback turtle crawling on shore

What Is The Largest Sea Turtle?

The Leatherback is the largest living sea turtle. It’s so named because of its unique shell that is composed of a layer of thin, rubbery, tough skin that is strengthened by thousands of tiny bone plates that give it a ‘leathery’ look.

They are the only turtles without a hard shell. 

They weigh between 550 and 2,000lbs and can grow up to six feet. Their head has a deeply notched upper jaw with 2 cusps. It has a large carapace that is elongated and flexible with 7 distinct ridges.

Only hatchlings have scales on their carapace. In adults, their carapace is dark grey or black with white or pale spots.

They also have a whitish to black plastron that is marked by 5 ridges. Meanwhile, hatchlings have white blotches on their carapace.

You can spot Leatherback sea turtles as far north as Canada and the northern Pacific Ocean.

However, they do prefer the tropics, tending to nest there. In the U.S. you can find the Leatherback nesting in southeast Florida, Puerto Rico, and the U.S. Virgin Islands. 

The Leatherback has been listed as endangered worldwide by the U.S. federal government. The biggest threats to the Leatherback include getting caught in commercial fishing nets, marine pollution, and the harvesting of eggs.

Do sea turtles have teeth?

No, turtles do not have teeth but there are fossils of turtle teeth! Odontochelys (or the ‘toothed turtle’) was a creature that existed about 200 million years ago.

It was discovered in their fossilised remains that this early ancestor of the modern turtle had teeth in both its upper and lower jaw.

Modern-day Loggerhead sea turtles (Caretta Caretta) are carnivorous however, and the largest Loggerheads turtles can weigh up to 450kg. To put that in perspective, that’s about the size of a dairy cow.

Still, turtles have beaks rather than teeth, and with their strong jaw muscles and tough beaks, carnivorous turtles can crush the shells of their crustacean prey like crabs, sea urchins, and clams. 

Baby turtles do have what’s called an ‘egg-tooth’ or caruncle but this doesn’t resemble a tooth. It’s actually a small bump made from the same protein our fingernails are made from – keratin. 

A big danger to sea turtles is plastic waste. This is because they swallow food without chewing, so mistaking a plastic bag for a jellyfish can be fatal. 

Do sea turtles sleep underwater?

Turtle sleeping on corals undersea

Sea turtles can sleep at the surface while in deep water, or they will wedge themselves under rocks in water near the shore. Many divers have spotted green turtles taking a nap under ledges in reefs and rocks. 

Hatchlings typically sleep floating on the surface, with their front flippers folded back over the top of their backs. 

Sea turtles can rest underwater without breathing for up to two hours, but when they need food or evade predators they need to surface for air more frequently. 

What is the rarest type of sea turtle?

The Kemp’s Ridley is the most endangered species of sea turtle, and in 1970 was listed in the United States under the Endangered Species Act as endangered. 

The only major breeding site for the Kemp’s Ridley is a small section of beach at Rancho Nuevo, Mexico.

They mate in mass synchronized nestings known as arribadas. This translates to ‘arrival’ in Spanish. The arribada occurs regularly between April and June. 

In 1942, a Mexican architect caught an estimated 42,000 Ridleys nesting at Rancho Nuevo in one day on camera. In 1995, only 1,429 Ridley nests were laid at Rancho Nuevo.

However, things do seem to be improving for the Kemp’s Ridley as over 7,100 nests were recorded at Rancho Nuevo in 2004.

This increase can be explained by both the full protection of nesting females and their nests, and how shrimp trawls in both the U.S. and Mexico are required to use turtle excluder devices (TEDs) to reduce the number of turtles getting caught in fishing nets. 

The name Kemp’s Ridley comes from Richard Moore Kemp who was the first to send a specimen to Samuel Garman at Harvard, but the origins of ‘ridley’ are unknown. 

Kemp’s Ridley have also been referred to as a ‘heartbreak turtle.’

In her book The Great Ridley Rescue, Pamela Phillps claims the name was coined by fishermen who witnessed the turtles dying after being turned on their backs. The fishermen believe the turtles had died of a broken heart. 

What is the smallest sea turtle in the world?

The smallest sea turtle is actually the rarest turtle – the Kemp’s Ridley! 

They measure less than 30 inches long and weigh less than 10 pounds. Unlike other sea turtles, Kemp’s Ridleys usually lay their eggs during the day. In the 1940s, an arribada would usually draw in around 40,000 females.

By the 1980s, due to uncontrolled collection of eggs and meat, the Mexican government enforced stricter provisions on egging (harvesting eggs for human consumption), and the U.S. has a nesting beach in Texas where more than 100 females have laid eggs yearly for the past decade or so.

The hatchlings are raised by biologists in captivity until they are able to survive in the wild, and then they are returned to the beach where they hatched. 

How old is the largest sea turtle?

The oldest sea turtle is said to be around 400 years old and is in captivity in the Guangzhou Aquarium in China, weighing 300 kilograms. Scientists are unable to determine the age of the oldest sea turtle in the wild. 

This is because most sea turtles almost never leave the ocean, especially males. This makes it particularly difficult to keep track of sea turtle populations and ages.

The Leatherback turtle is not only the largest sea turtle, but the oldest known sea turtle species too. It is believed to have existed for over 150 million years. 

Leatherback turtles also tend to live longer than other species of sea turtle, with a lifespan of up to 100 years.

Who is bigger? Turtle or Tortoise?

Most people use the term ‘turtle’ to refer to any reptile that has a shell, but while all tortoises are turtles, not all turtles are tortoises.

It can get a little confusing, but there are several key differences between these two creatures. Most notably, tortoises live mainly on land, and turtles are built for a life in the sea. 

Tortoises have evolved to live in their land-based habitats. They are larger, heavier, and bulkier than turtles. Their round, stubby feet help them to traverse rocky terrain.

These are often described as ‘club-like’ and may remind you of an elephant’s feet! Tortoises are carrying hefty shells, and their large hind legs not only help them to move around, but to carry their shells.

Tortoises also have sharp claws to help them to dig burrows. These burrows give them shelter not just from hot, dry environments but predators too.

Tortoise shells are also larger and are more domed, and they also play a part in protecting tortoises from the predators they encounter on land. 

So while tortoises have more round, domed shells, turtles have thinner shells that are more suited to their lives in the water.

They are streamlined to help the turtle swim, and turtles have a more streamlined body shape compared to the tortoises, most notably in their smaller, flatter, lighter shells. 

Turtles also have flipper-like legs, or webbed feet to help them glide through the water with ease. 

Turtles are omnivores, as they eat both animal and plant life depending on the species (the Loggerhead turtle, for example, is carnivorous). Turtles enjoy algae, insects, jellyfishes, sea sponges, and small fish.

Meanwhile, tortoises enjoy vegetation that is low to the ground, such as cacti, flowers, fruits, grasses, and shrubs. They are herbivores mostly, but some species of tortoises have been known to eat insects and worms. 

Turtles usually mate in the water or on the shore. Again, this all depends on the species of turtle.

While the large Leatherbacks can live up to 100 years, the average lifespan of a turtle is 20 to 40 years, and sea turtles can live to around 60 or 70 years.

It’s interesting to note that tortoises have a far longer lifespan than turtles, usually living around 80 years. But some tortoises have been known to live for well over 150 years!

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