9 of the Scariest Animal Mouths Out There

An animal doesn't have to be large to be frightening. Sometimes teeth are enough.

great white shark open pink mouth with pointy teeth

Stephen Frink / Getty Images

Being eaten alive is a common fear, and perhaps that is why the mouths of some animals are such terrifying sights to behold. In this regard, few animal mouths elicit fear quite like the gummy-pink jaws of a great white shark, pictured above.

There are some lesser-known creatures whose mouths are equally as unnerving as that of the prominent sea predator. Have you ever caught a glimpse of the humanlike pearly whites of a pacu fish? What about the protrusible jaw of a goblin shark?

Here are nine animal mouths that will put you on edge.

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front view of lamprey mouth, tube with many thorny teeth

PEDRE / Getty Images 

Lampreys might be jawless, but that doesn't make their thorny, suction cup-like mouths any less frightening. This parasitic fish uses its mouth like a funnel, targeting an animal's body and using its teeth to cut through surface tissues, then sucking out the blood and body fluid. It uses both its hooked teeth and strong suction power to hold on—and almost nothing can make it let go.

While lampreys may appear chilling, humans actually have the upper hand on them. They are commonly used in research because the simplicity of their brain is thought to reflect the brain structure of the earliest vertebrates. They are even enjoyed as food by humans all around the world.

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Leatherback Sea Turtle

Leatherback turtle oesophagus

Mdomingoa / Wikimedia Commons / CC SA 4.0

Reminiscent of something out of "Star Wars," the inside of a leatherback sea turtle's gullet appears to be full of teeth. In fact, they are papillae, backward-facing cartilage spikes made from keratin that line the turtle's entire esophagus.

Leatherback sea turtles use their barbed throats to consume—and keep hold of—their primary prey, jellyfish. The papillae trap the jellyfish, preventing them from slipping out when the turtle opens its mouth, while enabling it to expel excess water prior to swallowing.

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close up of tiger face licking its paw

Tennessee Wanderer / Flickr / CC BY-ND 2.0

Like the leatherback sea turtle, the tiger also sports needle-like backward-facing papillae in its mouth. However, for the big cat, these sharp barbs are found on the tongue.

Tigers use the papillae on their tongues to strip fur, feathers, and meat from their prey, all the way down to the bone. Like household cats, they help the tiger with grooming. The effectiveness of this harsh tongue has even inspired grooming products used by humans.

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Pacu Fish

front view of pacu fish with human-like teeth displayed

jean-claude soboul / Getty Images

Though the pacu fish is a relative of the piranha, the two do not share teeth. Piranhas have sharp, razor-like teeth, but the pacu, a South American freshwater fish, has squarer and straighter teeth that are eerily human.

Like humans, pacu fish are omnivores, though they maintain a mostly herbivorous diet. They feed primarily on fruit and nuts that fall into the water, using their anthropomorphic teeth to crack shells when necessary. To do this, they utilize their impressively strong jaw.

Pacu fish are generally non-aggressive and are commonly kept as pets before they grow too big.

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hippo submerged in dirty water with large mouth open wide

Enn Li Photography / Getty Images

The mouth of a hippopotamus is scary not because of how it looks but because of what it can do. These animals are known for their wide yawns where their jaws can open to almost a full 180 degrees. The yawns are primarily used for intimidation, which makes sense considering the large animal's territorial nature.

While the hippo's jaw can open wide, it can also close with a lot of power. The force of their bite measures approximately 1,800 pound-force per square inch, which places them among the strongest bites in the animal kingdom.

Despite all this, however, hippos are herbivorous, so you don't have to worry much about one biting after you. But they can still be highly aggressive toward humans and kill 500 people a year in Africa, on average, so keep your distance if you happen to see one.

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Goblin Shark

head of pinkish-gray goblin shark with long snout and many small teeth

Dianne Bray / Museum Victoria / Wikimedia Commons / CC BY 3.0 AU

At first glance, the goblin shark is an ugly creature. Its nail-like teeth and blank stare are outshined only by its long, flat snout, reminiscent of a broad sword blade. However, it's the goblin shark's mouth that sparks real fear.

Its jaws are high protrusible, meaning they can dislodge and project out. This ability is used during feeding when the goblin shark will extend its jaw to the end of its long snout to grab fish—and fast. In fact, they execute this "slingshot feeding" technique at 10 feet per second, the fastest movement of its kind ever recorded of a fish.

It's useful that goblin sharks' jaws are so quick because they allow for ambushing prey when they themselves are sluggish, slow swimmers.

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black with yellow manbill monkey with mouth open showing long teeth

Mathias Appel / Flickr / Public Domain

Mandrills are colorful primates with faces seemingly painted like a clown, but their mouths are much less of a joke. Their enormous canine teeth can grow to 2 inches long.

However, as scary as these teeth appear to be, mandrills likely have little intention of using them against you. While mandrills do use their teeth for self-defense, the surprisingly omnivorous primates more likely bare them to each other as a means of friendly communication. They use it a greeting signal.

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hand holding hagfish and showing off its pairs of teeth

ffennema / Getty Images

The hagfish is an eel-shaped fish with a cartilage skull but no spine. While known for its excessive production of slime as a defense mechanism, its mouth should not be ignored.

Surrounding the mouth are four sensing tentacles. Though the hagfish does not have a jaw, it does possess two pairs of comb-shaped teeth that are used for feeding on the carcasses of dead fish. They rip away chunks of flesh or burrow directly into the prey to access its innards, and then consume it from the inside out.

Hagfish can be found throughout the world's oceans, living in burrows on the deep ocean floor.

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Vampire Fish

black and white vampire fish with mouth wide open and two long teeth displayed

IGFA / Getty Images

Though more commonly known as payara, one look at the teeth on this fish and you can see why they're also named after vampires. The fangs that protrude from their lower lips are so long (up to 6 inches) that the fish require specialized pockets in their skulls to holster them in and prevent them from stabbing themselves.

They use their monstrous teeth to skewer fish before eating them. However, they don't typically go after anything that's too big to swallow, so consider yourself safe. They live in the Amazon Basin of South America and are a popular species in large, aggressive aquariums.