5 Alien Sharks You've Never Heard of

By AT&T Digital Media Productions editorial team


NOAA Ocean Exploration/Flickr


Sharks that live more than 984 feet below sea level are classified as deep-sea sharks, also known as “alien sharks.” The nickname works: these sharks are seriously out of this world, with pale skin, slimy bodies, and otherworldly eyes and teeth.

There are three groups of deep-sea shark: demon catsharks, deep-sea dogfish, and ghost sharks. Because they spend their lives in the darkest depths of the ocean, we don’t know much about them. But what we do know is fascinating. Though scientists used to think these species were extremely rare, now they’re not so sure—fathoms below the surface, there may well be a teeming, thriving ecosystem of these eerie sharks.



Dianne Bray, Museum Victoria/Wikimedia Commons

Perhaps the most notorious deep-water shark, the goblin shark looks like nothing else on this planet. It’s bubblegum pink, with a long blade-shaped snout. It can grow at least 18 feet long. And those membranous, toothy jaws are even freakier than they look: the goblin shark can unhinge both jaws and project its entire mouth forward several inches, nabbing prey like a mobile marine mousetrap.

Goblin sharks are rarely caught or encountered by humans. Researchers have gotten a sense of their range and physiology from the few unlucky specimens found in fishing nets or deep-sea trawls. Their habitat seems to be widespread: they’ve been found in deep waters on both coasts of the Atlantic and Pacific, from Japan to New Zealand, Mozambique, Western Europe, and the Caribbean coast of South America. And while they may be plentiful, nobody really knows how they reproduce, as a pregnant female has never been found.





With their slender bodies and greenish, catlike eyes, demon catsharks sure resemble their namesake. These bottom-feeders haunt the continental shelf throughout the world’s oceans. Like their shallow-water relatives, the horn sharks and other catsharks, these demons hatch from egg sacs.

There are five known species of demon catshark: the ghost, white ghost, Iceland, smalleye, and black roughscale catsharks. As with most deep-sea sharks, not much more than that is known: there could be hundreds of species with thousands of individuals, or the population could be tiny and vulnerable. They might eat shrimp.




The ghost shark isn’t a shark. Rather, it isn’t the kind of shark we know as a shark today. It’s a Chimaera, a family of ancient creatures that branched off from sharks 420 million years ago. For that reason, it’s known as a “living fossil,” or creature that existed in more or less its current form hundreds of millions of years ago.

Chimaeras live on the ocean floor up to 8,500 feet deep, where they feed on small fish and crustaceans. Their teeth aren’t sharp, but are instead fused together into grinding plates. Like modern sharks, they locate their prey with electroreception and lay eggs in leathery cases. Unlike modern sharks, the males have retractable genitalia on their foreheads.

There are several species of ghost shark, like the Rhinochimaera pictured above, and the deep-sea chimaera, below.




 NORFANZ Founding Parties/Wikimedia Commons


The Portuguese dogfish is the deepest shark of all. No, it doesn’t discuss philosophy with its fellow sharks—it’s been recorded at over 12,000 feet deep. These deep divers are fairly common worldwide (what predators could make it down that far?) and are even fished commercially.

Portuguese dogfish are vicious hunters, capable of taking down big, fast prey. And they’ve evolved to maintain top performance in the blackest depths: because sunlight doesn’t reach their habitat (not even close), they can detect the bioluminescence of their prey.



FLMNH Ichthyology/Wikimedia Commons

The megamouth shark is a shy, mysterious creature. Nobody even knew it existed until 1976, when one got caught on a U.S. Navy ship’s anchor off the coast of Hawaii. Since then, only 63 individuals have been caught or even seen. Of course, they do live 5,000 feet underwater.

The megamouth is not a great swimmer, with its soft, flabby body, and fewer fins for steering than more agile shark species. But that’s okay: like its better-known cousins, the whale shark and basking shark, the megamouth is a filter feeder. Instead of hunting for food, it sucks in vast quantities of tiny invertebrates as it drifts slowly through the water. Its mouth is surrounded by a luminous band of glowing pores, which may act as a lure for plankton in the sunless depths.


To catch a glimpse of more oddities of the deep, tune in to Shark Week, only on Discovery.


Sources: Discovery, Florida Museum, Elasmo Research, Oceana, Red List, Shark Trust, Britannica.