8 min read

10 Scariest Mouths of the Sea

Aaaahh, the serene and beautiful sea and its gentle waves lapping at the shore and sparkling in the sunshine. With 150 million visitors annually flocking to California’s beaches alone, it’s clear that most people enjoy the tranquil and rejuvenating ocean experience.

But do any of us really know what lurks beneath its surface? Turns out it isn’t all clownfish and dolphins. For anyone curious enough to peer beyond the usual depth, a whole new strange and frightening realm of deep-sea creatures awaits. Today we’ll explore the top 10 most mysterious mouths of the deep sea…and anyone brave enough can join us!

1. Monkfish

Monkfish have many layers of teeth and great camouflage for hiding on the seafloor.
Monkfish are among the most fascinating predators in the world. Also commonly called goosefish, fishing frogs, and more, these frightening bottom-dwellers are most commonly found on the continental shelves off of both North and South America as well as Africa, China, and Japan. They’re known for lying still on the ocean floor, waiting for a fish to become interested in their antennae, called an ‘esca’, which is actually a section of modified spine that works as a lure for them. They can also change their color to create better camouflage. As the unsuspecting fish comes in closer, the monkfish springs into action, grasping at prey that’s sometimes up to half its own size.

Their center-facing teeth are useful for trapping their prey, and their wide mouths and expandable stomachs make sure they can grasp and digest a good variety of creatures for dinner. While fish are their usual favorite, they’ve been known to travel to the ocean’s surface to nibble on waterfowl and otters when the seafloor pickings are slim.

While considered a delicacy in some parts of the world today, their name comes from the stories that monks would often end up eating them when asking for the unsold fish at the fish markets. Monkfish would often get passed over at the markets due to their unpleasant looks. Today they are gaining popularity across the globe as they’re rumored to taste like lobster but sell for much cheaper; in many places, they are called ‘the poor man’s lobster’.

2. Moray Eel

Don’t worry if it looks like they’re staring at you with their mouths open or laughing -- it doesn’t mean the moray eel is going to bite you. It’s just how they breathe! Just one of their unique, if not frightening traits, moray eels have gills and must keep water moving toward them in order to keep breathing. Keeping their mouths slightly open allows this to happen. It also allows their nightmarish teeth to be visible--but wait until you see the rest of their teeth!

Found predominantly in the warm waters of the tropical regions of the world, moray eels can be quite colorful and may also appear to be adorned with patterns--while at other times they may just be upping their camouflage from a basic brown hue. Their skin is often covered with mucus which protects them from harm as they dash about the rough edges of the reefs they call home. While this mucus protects them, some of it can be toxic to other creatures, namely humans.

But without a doubt, the most amazing feature of the moray eel is its pharyngeal jaw. Ever seen the movie Alien?

Yep, it’s kind of like that. A literal second set of jaws can shoot forward from within the eel’s throat, grasping their prey to hold it firmly while they swallow.

Another interesting feature of the moray eel is their tendency to hunt with grouper fish. Groupers shake their heads at the eels to notify them that it’s time to hunt, and the eel agrees, trapping the prey for them. But what happens if the eel tries to leave before the grouper decides the hunt is over? The grouper eats them! The deep-sea sure is a wild place.

3. Sea Lamprey

According to the Great Lakes Fishery Commission, sea lampreys are highly adaptable creatures with many unique traits, even said to have survived the last four major extinction events. How do they do it? Let’s start by checking out that mouth.

Seen mainly in the Atlantic Ocean, lampreys found their way into the Great Lakes via the Welland Canal, where they are considered an invasive species. To feed, the lamprey clamps its oval-shaped mouth onto its host animal, suctioning on tight and sinking its keratinized teeth in, scraping scales and flesh apart to slurp fresh blood and body fluids with its rough-edged tongue in the center. Meanwhile, to prevent the prey’s blood from clotting, the lamprey secretes a fluid called lamphredin that keeps it flowing. This is called hematophagous feeding.

Their favorite prey includes lake trout, sturgeon, walleye, catfish, whitefish, herring, and other species of large Great Lakes fish as well as Pacific and coho salmon and steelhead. After a year of hematophagous feeding, lampreys find their way back to the freshwaters where they were born to spawn and then die.

4. Leatherback Sea Turtle

Many folks fail when trying to guess which animal this mouth belongs to -- and it’s easy to see why! Who would dream this was the inside of a gentle sea turtle’s mouth? Surprised? Yep, sure enough, it’s a leatherback sea turtle mouth, complete with hundreds of backward-facing papillae lining not only the mouth but also down into the turtle’s esophagus and even their belly.

Why do they have such “teeth”? Their favorite food gives us a clue about that. Jellyfish, which sea turtles adore, make up the majority of their diet. In one day, for example, a leatherback can eat nearly 75% of their body weight in jellyfish! And as slippery as jellyfish are, the turtles need a firm grasp to hold them in their mouths. Their lengthened, looped esophagus helps get it all digested, too. All this jellyfish eating helps make them the third-largest living reptiles in the world, often growing up to four or even six feet long and weighing over 1,000 pounds.

The problem? Turtles can’t tell the difference between jellyfish and floating plastic bags in the water. With the leatherback being endangered already, we certainly don’t need to add to their problems. Let’s be more careful with our trash and see about trading in the one-use plastic bags for reusable canvas bags so these amazing creatures can stay with us on the earth!

5. Black Dragonfish

Black dragonfish are next on our tour, and they can surely hold their own spot in line for alien-looking features. To start with, their deep, black bodies blend in with the dark depths of the sea, giving them a nice camouflage to hide in and keep their prey unsuspecting. Their long, super sharp teeth are transparent, so they’ll continue to be invisible to prey. Then they emit a light near their mouths which acts as a lure to draw curious fish near. Finally, their remarkably large mouth can widen enough to swallow creatures nearly half their size.

Researchers at the University of California San Diego explained in a recent article how black dragonfish teeth develop using an electron microscope. The teeth are extremely sharp, even sharper than piranha teeth, but they consist of tiny nanocrystals in the enamel that prevent the teeth from reflecting light. This is where the transparency comes in. Aside from that, their teeth are made of dentin and are very thin, which also contributes to their transparency. With all that camouflage, the dragonfish’s prey is in for a surprise indeed!

6. Sperm Whales

Sperm whales are the largest animals with teeth!!!
The largest animal in the world with teeth is the whale — namely the sperm whale—since the only whale larger is the baleen whale, which is toothless. The sperm whales have between 18 and 26 teeth on each lower jaw which fit into sockets on the upper jaw. While this would seem to be useful in the hunting of prey, many sperm whales with missing teeth and deformed jaws have been found with full bellies—so the sperm whale’s teeth actually exist without any certain purpose.

In any case, sperm whales do use their teeth to grab their prey, and their preferred menu items include squid and fish.
Fun facts about sperm whale teeth:
  • As sperm whale teeth grow, clear layers of dentine and cementum are observable, similar to how trees grow in rings that can be read to reflect their age.
  • They’re typically 8 to 10 inches long at full adult size.
  • They used to be made into buttons and pipes.
  • When JFK was laid to rest after his assassination, his wife Jackie placed one on his chest. It was a Christmas gift she’d purchased for him earlier in the year. (8)

7. Sharks

Naturally comprising fluoride, the ingredient in toothpaste that helps prevent cavities in humans, there’s no surprise to find that shark teeth never get dental caries. Known as apex predators within the marine ecosystem, sharks have unique teeth that stay sharp and also constantly regrow, ensuring they always have a full set of sparkly whites for grabbing, twisting, and tearing the flesh of their prey.

They’re grown in rows, generally between 5 and 15 of them (but the Bull Shark has 50!), and a shark may lose a tooth at any random point in the row. When this happens, the tooth behind it moves in to replace it, and so on and so forth. On average, sharks lose approximately one tooth per week, which can be replaced within one single day. In time, the smaller teeth in the back rows work their way up to replace the larger front teeth.

8. Crabeater Seals

While it may seem logical that the Crabeater Seal’s teeth are shaped to crack open crab shells, the truth is they eat mainly Antarctic krill. So, what’s with the zig-zag serrated teeth?

Chicago Field Museum Collections Manager Bill Stanley explains the seals, their teeth, and their feeding preferences: They use them in the same way you and I would use a pasta strainer. They “scoop” up a bunch of water with plenty of krill in it, then strain it out through their teeth, keeping the krill trapped inside to munch on when the water’s gone.

Tiny microscopic krill makes up more than 90% of the crabeater seal’s menu, and regardless of its name, the creature never really eats crab at all. Stanley says that "the same thing that sustains 100,000 of these [crabeater seals] also sustains the 100-foot-long blue whales." Can that be true? Indeed, it can. Surprisingly, krill have an estimated biomass of 500 million tons and are often thought to be the most abundant species of all.

9. Pacu Fish

The Pacu fish, which are omnivores, have remarkably human-like teeth. Their teeth are mostly aligned in a single row. Their preferred menu includes the foods that fall into the water where they live, which is usually nuts and fruits, but they can use their super-strong jaws and teeth to crack the shells of other types of prey when need be. They also eat plants, algae, and small fish.

Pacu fish are native to South America, and include several species with the deadly piranha being featured in their subfamily--although Pacu are usually not aggressive, and in fact are often referred to as ‘vegetarian piranhas’. Many people keep them in aquariums as pets when they are small, but they grow very quickly up to and past three feet long and continue growing throughout their lifetimes. They ultimately require 500-gallon fish tanks, which most people don’t have.

10. Humpback Anglerfish

Found widely throughout most of the world’s oceans, but mainly in the deepest waters of the Atlantic and Antarctic, there are over 200 different species of Humpback Anglerfish. Another creature with sharp, transparent teeth, the Anglerfish varies in size from one to approximately three feet long and ranges in color from gray to dark brown. Female Anglers have the esca, or the piece of dorsal spine hanging with the “lure” above their mouths, which attracts unsuspecting prey with bioluminescence created by symbiotic bacteria. In this case, the Anglers’ mouths are wide enough to consume prey up to twice their size.

A few fun facts about Anglerfish are:
  • The Humpback Anglerfish’s teeth are angled inward which helps keep prey from escaping.
  • The Angler’s translucent teeth can grow up to 3.5 feet in length.
  • The female Anglers are more dominant and fiercer hunters than the males.

    At Jungle Roots Children’s Dentistry & Orthodontics, we strive to provide the highest comprehensive pediatric and orthodontic dental care in a unique, fun-filled environment staffed by a team of caring, energetic professionals. We believe the establishment of a “dental home” at an early age is the key to a lifetime of positive visits to the dentist.

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