Wondering whether snakes have bones? A lot of people are surprised by the answer. The fact is snakes do have bones and lots of them.
Every species of snake has bones, but snakes don’t have many different types of bones. A snake’s skeleton is made up primarily of vertebrae, rib bones, jawbones, and a skull. Some species, like boas and pythons, also have a hip bone. Depending on the size and species, snakes can have anywhere between 600 to 1800 bones.
Now that you’ve satisfied your curiosity, let’s take a look at snake bones in a bit more detail.
Do Snakes Have Backbones?
All snakes are vertebrates, which means that they all have backbones. In fact, snakes have more backbones (or vertebrae) than any living mammal.
In a snake’s body, many tiny backbones are connected by hundreds of joints and a strong network of muscles, which is what gives snakes their extreme flexibility.
The number of vertebrae depends on the size and species of the snake, but all snakes have an unusually high number of vertebrae compared to most other vertebrates. Snakes actually have 2 main types of vertebrae:
|Precaudal vertebrae:||The vertebrae found in the snake’s body|
|Caudal vertebrae:||The vertebrae found in a snake’s tail|
Depending on the size and species, a snake could have anywhere between 100 and 450 vertebrae in the main part of its body (precaudal vertebrae), and as low as 10 to as many as 205 caudal vertebrae in the tail.
Each precaudal vertebrae (the ones in the main body, not the tail) is attached to a pair of ribs.
So, let’s say that a snake has 450 backbones in the main part of its body. If that’s the case, then it will also have a total of 900 rib bones.
As I’m sure you can work out, this means that a snake’s skeleton is mostly made up of ribs. Actually, around 70% of a snake’s bones are rib bones.
A snake’s vertebrae and rib structure make up the majority of its skeleton, which is connected in a way that allows the snake to be incredibly flexible.
Snake vertebrae connect with each other at 5 different points, meaning that they can swivel, rotate and twist with ease.
Because of the huge range of motion that is built into a snake’s skeleton, coupled with the lack of a sternum (snakes don’t have a breastbone that connects the ribcage), a snake can actually expand its rib cage to an astounding degree, making it super easy to swallow large prey whole.
How Many Bones Do Snakes Have?
Snakes can have anywhere between 600 and 1800 bones.
Scientists look at the broad belly scales (called ventral scales) and the dorsal scales on the body of the snake.
These scales correspond to the number of vertebrae, so they can use the scales to figure out the number of vertebrae in a live snake.
If you want to know how many bones a snake has, you first need to count the number of vertebrae in both its body and in its tail.
Next, you need to calculate how many rib bones the snake has.
You do this by simply doubling the number of precaudal vertebrae. Do you remember which ones they are? – if you guessed the ones in the main body – you’re absolutely right!
Add on the number of vertebrae in the snake’s tail, and the small number of skull and jawbones (around 10), and you will get a pretty good idea of the total number of bones in a snake’s body.
The Royal Society Journal found that the number of vertebrae in snakes is directly correlated with a snake’s body size, so the bigger the snake, the more vertebrae it will have.
To get to this conclusion, the experts measured several snakes, most notably boas and pythons, and counted the number of vertebrae. Here’s a snippet of what they found:
- The average number of vertebrae in pythons that measured between 7 and 9 feet long was 300. Making the total number of bones (including rib and skull bones) approximately 850.
- Boas of approximately 5 feet had an average of 250 vertebrae, bringing the total bone count to around 700.
- The highest number of vertebrae they found (in a python) was 450. When they added up all the other bones (pairs of rib bones, skull, and jawbones) the total number of bones was 1200.
Do Snakes Have Skull Bones?
A snake’s skull bone is perhaps the most crucial and fascinating bone in its entire body. Here’s why:
A snake’s brain is entirely encased in bone to protect it against struggling prey
Since the snake’s mouth and the brain are so close together, and snakes tend to swallow their (rather large) live prey whole, the snake’s brain could easily be damaged.
The skull bone has therefore cleverly evolved to completely envelop and protect this vital organ.
Skull sizes and shapes vary wildly in snakes.
From an evolutionary perspective, both the strength of the braincase and the size and shape of a snake’s skull can be linked to the particular features of a species habitat.
A snake hears through its skull bones
Snakes don’t have any ears, but they do have a few skull bones and jawbones that allow them to receive and detect soundwaves.
The way that snakes hear is called bone conduction and it works because they have a sensitive and very basic inner ear structure.
According to the Journal of Experimental Biology, snakes can hear because they have a single inner ear bone that vibrates inside the skull.
It’s called the columella auris, and it’s connected to the snake’s jawbone.
A snake’s skull is very flexible to allow it to stretch and expand to consume prey.
A lot of people think that snakes unhinge or dislocate their jaw to consume prey. Not so.
Snakes can open their mouths incredibly wide because of a couple of stretchy ligaments and a very important bone, which is found in the skull.
The quadrate bone is a bone at the back of a snake’s skull that is attached to the main part of the skull by some very stretchy ligaments.
The quadrate bone works like a double-hinged joint, allowing most snake species to open their jaws up to approximately 150 degrees.
Instead of a chin bone connecting their jawbones together as we humans have, snakes have a stretchy ligament that connects the two halves of their jaw (called the mandibles) together.
You can clearly see the gap where the stretchy ligament would be (at the bottom of the jaw) on the picture below:
As Kenneth V Kardong explains in his article for Coepia, the configuration of the cranial bones and their attachment to this stretchy ligament is what allows snakes to increase their jaw width or “gape”.
So, it turns out that snakes do have bones. What’s more, all those tiny little interconnected bones are what allow snakes to move, bend, twist, rotate and expand and contract their jaws and ribs so effortlessly.