Why Do Giraffes and Humans Have the Same Number of Neck Bones?

The world is populated with an amazingly diverse animal kingdom, each species possessing its own unique features that help them survive and cope with their surroundings.

There’s the cheetah with its incredible burst of speed, the albatross that has a wingspan of over 3 meters and the groundhog which is the largest member of the squirrel family.

There are sharks that can spot a drop of blood in the vast ocean and bees that help pollinate flowers and keep our eco-system going.

And then there’s the giraffe, the animal with the longest neck in the world.

How Long is a Giraffe’s Neck?

There are few things that are quite as magnificent as seeing a giraffe in the wild. The giraffe is native to Africa, a herbivore and the largest land mammal that is currently living on our planet.

The tallest one on record was around 19.3 feet, about the size of an average house, maybe a little higher. It’s the elongated neck that grabs most of the attention, though, and that alone can weigh as much as 550 lbs. 

The reason most people think that giraffes have such long necks is to help them feed – they can reach higher than other animals and so can get the choice leaves up in the trees. As with all things in the animal kingdom, the truth is a little more complicated and a lot less certain.

There is little evidence that feeding is the reason the long neck evolved and the current theory is that it helps males compete for females during the mating season.

An astounding side effect of the long neck is that the giraffe needs a powerful heart to pump blood up to the head and brain. It, therefore, has the highest blood pressure of any animal on the planet.

One other interesting fact that most people don’t know is that this elegant mammal has the same number of bones in its neck as us humans.

The Human Neck

Compared to the giraffe, human neck length is pretty paltry, to say the least. However, when looking at the anatomy of the human spine, you will find that, like the giraffe, humans have 7 cervical (neck) vertebrae.

Compared to other species, the neck area of the human can be quite fragile which is why it is often subject to accidents like whiplash when the head moves suddenly back and forth. The giraffe neck, particularly in males, is surrounded by thick blocks of muscles that protect it.

Why Do Giraffes and Humans Have the Same Number of Neck Vertebrae?

You might be impressed by the fact that humans have the same number of cervical vertebrae as a giraffe. But so does a mouse. And a kangaroo.

In fact, the vast majority of mammals have 7 cervical vertebrae. There are only two mammals that don’t and these are the sloth and the manatee.

Other animal species have different numbers of vertebrae in the neck. For example, a swan has around 22 bones in its neck. But for most mammals, it’s 7.

It’s the size of the bones that vary, of course, which is the reason that the giraffe’s neck is much longer than that of any other mammal. Each vertebrae can be up to 10 inches long. Compare that to a mouse which is barely  4 inches from the tip of its nose to the end of its tail.

Sloths and Manatees

While there is a huge amount of similarity between mammals, there are always exceptions to the rule in nature. In this case, it’s the sloth and the manatee that fail to conform.

Two-toed sloths have somewhere between five and seven cervical vertebrae while the three-toed sloth has between eight or nine. In species with more vertebrae, some of these also come with attachments for the rib cage. Manatees, on the other hand, have just six cervical vertebrae.

A Common Characteristic of Mammals

While the fact that giraffes have the same number of cervical vertebrae as humans is interesting, it’s actually not that unusual. The vast majority of mammals have seven and the size of the vertebrae is the thing that differs, not the number. The only mammals that have more or less than seven vertebrae in the neck are sloths and manatees.