Skip to Content

How Wide Can a Snake Open its Mouth?

How Wide Can a Snake Open its Mouth?
This post may contain affiliate links. If you click one of these links and make a purchase, I may earn a commission at no additional cost to you. In addition, as an Amazon Associate I earn from qualifying purchases.

Snakes are pretty incredible animals. They have no limbs, they smell with their tongues, they don’t have external ears, and they can swallow something much bigger than their head.

But how exactly do they swallow something bigger than their head? Have you ever wondered how wide a snake can open its mouth? 

Personally, I have a pet snake. His name is Inverse and he is a California Kingsnake. As a snake owner, I need to know the appropriate size of food for him to eat at different stages of growth.

At first, it can be surprising how big of a rodent your snake can eat, especially when they’re a little hatchling.

How wide can a snake open its mouth?

On average, a snake can open its mouth up to 4 times wider than the girth of its body. The girth is the widest part of its body.

Generally, their mouths can open 150 degrees and sometimes even wider than that. The Boomslang snake can open up to 170 degrees, for instance.

Do snakes really unhinge their jaws?

Snakes do not unhinge their jaws, because there actually isn’t anything to unhinge. The snake’s jaw is connected by very stretch ligaments both at the back of the jaw and in the center of the bottom jaw so that the jaw can stretch open vertically and horizontally.

They also have a vertical bone on each side of the back of the jaw, called a quadrate bone, which allows them to open their mouths much wider than we humans can.

How do snakes eat?

California Kingsnake

Snakes will usually eat between 75 to 100 percent of their size each meal. Unlike us, they don’t eat three meals a day. Snakes eat as food is available to them, so it is beneficial for them to eat a large meal all at once. 

In the wild, a snake can go about 6 months without food if it has to. Certain kinds of snakes can even survive up to 2 years without food! They do this by lowering their metabolism up to 70% and using their stored energy to get by until their next meal is available.

In order to avoid being injured by its fighting prey, constrictors will squeeze their prey until they sense the prey’s heart stop beating. After that, they will smell for the prey’s saliva and start eating that end (the head) first, while stretching their jaw ligaments to fit the prey in its mouth.

The bottom jaw is made up of two separate jaws, a left and a right jaw. The ligament in the middle connects the two sides, but allows them to move independently. This ligament is stretchy like the ligament at the back of the jaw.

A snake will use this independent jaw movement along with its curved teeth to walk its prey further into its mouth. Since they can move each side of their jaw separately, they will move one side, then the other, further back down the prey to keep it moving until the internal muscles take over by squeezing the food down to the stomach.

How often do people get bit by snakes?

A lot of people are afraid of snakes. In fact, snakes are one of the most feared things on the planet. But most of the time, you really don’t need to be scared. 

You’ve heard of the “fight or flight” response. Most snakes will take the flight approach whenever possible. If you leave them alone, they will usually leave you alone.

Different species of non-venomous snakes copy characteristics of venomous snakes to scare predators away, even though they lack the venom to do real harm.

My Kingsnake, Inverse, for example will shake his tail to imitate a Rattlesnake. It’s just a Kingsnake’s way of warning you that you are putting them in an uncomfortable situation and that they want you to back off. 

California Kingsnake

California Kingsnakes also have colors that mimic a venomous water snake. Other Kingsnakes and Milksnakes have colors that mimic Coral snakes.

Back to the question – how often do people get bit by snakes? In the United States, about 7,000 to 8,000 people are bitten by a venomous snake each year, mostly residing in states like Florida and Texas.

On average, 5 people may die per year in the U.S. from a venomous snake bite. In comparison, an average of 51 people die from being struck by lightning each year in the United States.

Countries with larger venomous snake populations do have a higher rate of snake bites because there are more snakes around.

The most common reason for a snake biting a person is that it feels threatened and/or cornered. Take precautions if you are in an area where snakes may be resting.

Does a snake open its mouth only to bite or eat?

Snakes are seen with their mouths closed most of the time. If they do open their mouths wide, they aren’t necessarily striking and trying to bite. 

Snakes will “yawn” occasionally, which can be a way to smell/taste their surroundings better or even to relocate their jaw after taking in a big feeding.

Here’s a great video by CrystalsCreatures that covers a bit more about snake yawns and also shows the quadrate bone and stretchy ligament we were talking about in action.

In a more serious case, if a snake is keeping its mouth open or opening it frequently, it may have a respiratory infection which needs to be seen by a veterinarian as soon as possible. Snakes only have one functioning lung, so a respiratory infection is especially deadly for them. 

Other symptoms of a respiratory infection in snakes are a rattling sound when breathing or the snake keeping its head elevated.