Do Turtles Have Backbones?

Yes, turtles do have backbones. ‘Backbone’ is another word for the spine and describes the interconnecting bones called vertebrae which run along the inside of the top of a turtle’s shell.

The backbone is an important part of a turtle’s skeleton as it houses and protects the spinal cord which supplies nerves to the rest of the turtle’s body.

Turtle Skeleton | Photo 70033427 © Verastuchelova | Dreamstime.com

Do turtles have backbones?

It’s understandable that the question over turtle backbones can cause some confusion. Turtles are one of the more unique reptiles everything apart from their legs and head is encased in a strong shell.

The belief that the shell is the same as the backbone is a pretty common misunderstanding. The truth of the matter is that the backbone sits directly against the underside of the turtle’s shell where it actually fuses together with the shell itself. 

This doesn’t mean that they are the same thing. The backbone protects the spinal cord and offers an attachment point for other parts of the turtle’s skeleton including its ribs, pelvis, head, and shoulder blades.

When you look at the inside of a turtle shell, you will see that the backbone blends in with the shell. This is a process called ossification which fuses the bones of the spine to the bone of the inner shell.

Are turtles vertebrates or invertebrates?

The word vertebrates is derived from the Latin word vertebratus which means ‘joint of the spine’. Animals classed as vertebrates include all mammals, birds, and fish. Because turtles have a backbone, they are therefore classed as vertebrates.

By contrast, invertebrates are animals which don’t have a backbone, such as snails, insects, crabs, and jellyfish.

Turtles are also part of the reptile family, meaning that they are cold-blooded, breathe air, and lay eggs as well as having a backbone. Other animals in the reptile classification include crocodiles, snakes, and lizards. Turtles, and their close relatives tortoises, are unique reptiles because they are encased in a shell.

Is a turtle shell a spine?

Although a turtle’s shell is not technically part of its spine, the two are continuous with each other. The spine and ribs fuse together with a layer of dermal bone on the inside of the shell.

Dermal bone is different to the bones in a skeleton because it is formed by ossification of cells which usually make up membranes and skin. In turtles, this dermal bone is then topped with keratin, a kind of hard tissue also found in human hair and nails as well as horse hooves.

Can a turtle move its spine?

Turtles are unable to move their spines. This is what makes turtles such interesting animals – because their spine is fused with the bones of their shell, they aren’t able to bend their spine like other vertebrates.

A common misconception about turtles is that they can leave their shells if they get too big. In reality, their shell is an extension of their skeleton and is as much a part of their anatomy as a skeleton is to a human. Luckily for turtles, this isn’t a problem because the shell grows with the rest of the turtle’s body.

How many bones does a turtle have?

It is perhaps unsurprising to learn that turtles are almost entirely made of bone. The turtle’s shell alone contains around 60 different bones but they also have bones in their neck, head, tail, pelvis, and flippers.

How big do turtles get?

Turtles can be small enough to fit in the palm of your hand or longer than the average sized human. The largest species of turtle alive today is the leatherback turtle. These incredible animals can be found in tropical and temperate marine environments across the globe.

The World Wildlife Federation estimate that the world’s largest leatherback turtles weigh between 600 and 1,500 pounds and can measure between 4.5 and 5.23 feet long. The largest species of freshwater turtle is the North American Alligator Snapping Turtle which can reach over 200 pounds and measure up to 2.5 feet long.

How important is a turtle’s shell?

A turtle shell is more than just a home. It is also a defense against predators and the site of biological processes that provide the turtle with vitamins and minerals. Turtles absorb vitamin D from the sun just like humans do and without this they can become sick.

Turtles are unable to live without their shell, so it is vitally important to their wellbeing. If they were to lose their shell, they would die. This can be a problem, as there are problems that can cause a turtle’s shell to rot.

Conclusion

Turtles do indeed have backbones inside of their shells. Their backbones are fused together, so they are unable to bend their backs (unlike most mammals). A turtle’s spine isn’t part of its shell, however.