The frilled shark is basically a living dinosaur that’s been swimming around our oceans for 80 million years, and it looks so ancient and weird that scientists rightfully refer to it as a living fossil. Of course, these creatures are a far cry from your Great Whites. They keep themselves to themselves, which is why it’s nearly impossible to catch a glimpse of them in real life.
1. They look like prehistoric sea serpents.
Frilled sharks have long, eel-like bodies that can grow up to 6 feet long, and their most distinctive feature is the frilly gills that look like ruffled collars around their necks. They genuinely look like something from a monster movie rather than a real animal.
Their snake-like appearance and primitive features make them look almost exactly like ancient sharks from millions of years ago. When people first see photos of frilled sharks, they often think they’re looking at some kind of sea monster or mythical creature.
2. They have 300 needle-sharp teeth arranged in 25 rows.
Each tooth is designed like a three-pronged hook that curves backwards, making it impossible for prey to escape once they’ve been bitten. The teeth are perfect for grabbing slippery squid and fish in the dark depths of the ocean.
Unlike great whites that have triangular cutting teeth, frilled sharks have grabbing teeth that work like hundreds of tiny fishing hooks. Once something gets caught in their mouth, those backwards-curving teeth make escape practically impossible.
3. They live in the deep ocean twilight zone.
Frilled sharks spend most of their time between 500 and 4,000 feet underwater where sunlight never reaches, and the water pressure would crush a human instantly. They’re perfectly adapted to this alien environment that we know less about than the surface of Mars.
The deep ocean where they live is pitch black, freezing cold, and almost completely unexplored by humans. These sharks have evolved to survive in conditions that would kill most other animals within seconds.
4. They can unhinge their jaws like snakes.
When hunting, frilled sharks can open their mouths incredibly wide by dislocating their jaw joints, allowing them to swallow prey that’s almost as big as their own head. This snake-like ability makes them incredibly effective predators in the deep ocean.
Most sharks can’t do this jaw-unhinging trick, but frilled sharks have kept this ancient ability that helps them catch large squid and fish. It’s like having a built-in expandable stomach that lets them take advantage of any meal they encounter.
5. They’re ambush predators that strike like lightning.
Despite looking slow and eel-like, frilled sharks can launch themselves forward with incredible speed when they spot prey, coiling their body like a spring and then striking faster than the human eye can follow.
They hang motionless in the water column waiting for squid or fish to swim by, then explode into action with a burst of speed that’s completely unexpected from such a primitive-looking creature. Their hunting style is more like a snake than a typical shark.
6. Pregnancy lasts up to 3.5 years.
Female frilled sharks have the longest pregnancy of any vertebrate animal on Earth, staying pregnant for between 2 and 3.5 years before giving birth to live babies. This incredibly long gestation period is partly due to the cold, slow metabolism of the deep ocean.
By comparison, elephants are pregnant for less than 2 years, and humans for just 9 months. The baby frilled sharks develop very slowly in the cold depths, and mothers might only reproduce once every few years.
7. They barely move to conserve energy.
In the food-scarce deep ocean, frilled sharks have evolved to move as little as possible, drifting through the water like ghosts and only using energy when they absolutely have to hunt or escape danger.
Their metabolism is so slow that they might not eat for weeks or even months between meals, and they’ve become masters of energy conservation. This zombie-like lifestyle helps them survive in one of Earth’s most challenging environments.
8. They glow in the dark.
Like many deep-sea creatures, frilled sharks have bioluminescent properties that make parts of their body glow with an eerie green or blue light, helping them communicate with other sharks and possibly confuse prey in the pitch-black depths.
This natural lighting system works like underwater glow sticks and is created by special bacteria or chemical reactions in their bodies. The ghostly glow makes them even more mysterious and alien-looking than they already are.
9. Scientists rarely see them alive.
Most of what we know about frilled sharks comes from dead specimens that get caught in fishing nets or wash up on beaches because they live so deep and are so rarely encountered that seeing one alive is incredibly special.
When Japanese aquarium workers managed to film a live frilled shark in 2007, it made international news because it was such a rare and exciting discovery. The footage showed just how alien and prehistoric these creatures really look when they’re swimming.
10. They’re perfectly designed killing machines.
Every part of a frilled shark’s body is optimized for hunting in the deep ocean, from their flexible spine that lets them strike like a snake to their sensitive lateral line system that can detect the tiniest movements in the water.
Their primitive design has worked so well for 80 million years that they’ve barely needed to evolve, making them one of nature’s most successful and unchanged predators. They’re living proof that sometimes the oldest designs are still the best.
11. They can grow new teeth constantly.
Like all sharks, frilled sharks continuously shed and replace their teeth throughout their lives, potentially growing thousands of new teeth over their lifetime to keep their deadly arsenal sharp and ready for hunting.
This conveyor belt of teeth means they never have to worry about wearing out their most important hunting tools, and they can bite through tough squid and fish without losing their effectiveness. It’s like having a self-sharpening set of knives that never gets dull.
12. They might live for over 100 years.
Scientists believe frilled sharks could live for a century or more because of their extremely slow metabolism and the stable, cold environment of the deep ocean, where they don’t face many of the stresses that age other animals.
Their ancient lifestyle and perfectly adapted bodies mean they might be some of the longest-living sharks on Earth, though studying them is so difficult that we’re still learning about their incredible biology and life cycle.