Hippo Mouth: Size and Facts

Hippos are some of the earth’s largest land animals. Their name derives from Greek when they were called “river horses,” although “river cows” might have been a better description. These ferocious animals are one of the most famous creatures around. They have huge mouths with long teeth and an impressive bite force. But what else is there to know about them? Let’s take a look and learn about hippo mouths: their size and facts.

What Does a Hippo’s Mouth Look Like?

As one of the largest in the animal kingdom, it’s no wonder that their mouths are built to match. Generally, the first thing that people notice is their teeth. Hippos have three sets of teeth: incisors, canines, and molars. The most noticeable ones are the incisors and canines, as they are long and ferocious-looking, appearing prominently at the front of their mouth.

Aside from their teeth, we can see their lips and interior. Hippo lips are specially adapted to be large and bony. Per day, they need around 100 lbs of food to keep their weight up, and all of it is from vegetation. Since their days are almost exclusively spent foraging the river banks and bottoms for plants, their lips have adapted to allow them to grasp and pull. With their immense strength and special lips, hippos can pull even deeply rooted plants out of the mud to eat.

When a hippo opens its mouth, one of the most distinctive elements you can see is its orbicularis oris muscle. When their mouths are closed, it’s not visible, but it’s actually what allows them to open their mouths so wide. The muscle is on the inside of their cheeks and can unfold (similar to an accordion) when stretched. This allows them to open their mouths wide without hurting themselves.

How Big is a Hippo’s Mouth?

Hippos are known for their size, and their mouths may be their most defining characteristic. Although the blue whale holds the top spot for the largest mouth on earth, the hippo may just take the prize for the largest mouth on land.

Generally, hippo mouths measure two feet wide (from left to right) when closed. It’s when they open it, however, that it really gets big. Hippos can open their mouths 150 degrees, essentially a flat line from top to bottom. This is often used to display their teeth to a threat, but it also happens when they yawn. At full stretch, hippo mouths can measure four feet tall.

Their special muscle (the orbicularis oris muscle) unfolds when they stretch their mouth, allowing them to get almost perfect rotation. Take a look at a hippo’s mouth while it’s opening to see this strange (and cool) muscle at work.

How Strong is a Hippo’s Mouth?

Hippos are some of the strongest animals on earth and, resultingly, have one of the strongest mouths on earth. It’s generally accepted that hippos have a bite force of around 1,800 psi. The figure was measured while looking at hippo bite victims in a medical lab, so it’s reasonable to trust it.

There is a common belief that a hippo could “bite a crocodile in half,” but it’s not really true. It’s better to think of it as hyperbole, although there is some truth to the underlying claim. Hippos and crocodiles do share the same territory in Africa, and that often results in fights. There have been reports (and likely videos) of hippos attacking crocodiles, but not specifically of them biting one clean in half.

Hippo Teeth

There are three sets of hippo teeth that we generally look at: canines, incisors, and molars. Canines and incisors are the long teeth that we generally consider as “tusks” at the front of an animal. In humans, canines are the sharp, pointy teeth at the corners of your mouth, and the incisors are the front four teeth. In hippos, these teeth have evolved to form long and dangerous weapons used for self-defense.

Their incisors (the two front teeth on the top and bottom) can grow to 1ft 4ins. Their canines (the front teeth on the outside edges of their mouths) can grow up to 1ft 8ins. The teeth never stop growing and self-sharpen every time they close their mouths. Additionally, their lower teeth grow larger than the top ones.

Hippo molars aren’t as imposing as the other teeth, but that’s for good reason. Molars are designed for chewing plant material and not for defense. For hippos, their molars allow them to process the large amounts of plant material they take in each day.

Do Hippos Have Tusks?

Hippos do have tusks, but they are actually their incisor and canine teeth. They are used for self-defense, mostly when it comes to other hippos in their territory. Hippos also have ivory, but it is often considered inferior to other forms (such as in elephants). It’s harder and yellower than elephant ivory, making it harder to carve and visually less appealing to some. Still, hippo ivory is a business model in parts of Africa, mostly as a result of the tightening of restrictions on elephant ivory.