Greenland Shark. Credit: Lars von Ritter Zahony / Ocean Image Bank.
The ocean is home to more than 549 known shark species, yet most people can name only a handful. Beyond the familiar great white, hammerhead, and tiger shark lies an extraordinary world of little-known species that have evolved remarkable adaptations to survive in coral reefs, polar seas, and the deep ocean. From sharks that glow in the dark to species that resemble carpets, these overlooked animals reveal just how diverse and fascinating sharks truly are. New discoveries are being made every year, including a new species named after Rob Stewart, reminding us how much of our oceans remain unexplored. Industries have begun to push farther into the deep sea through destructive activities such as bottom trawling and seabed mining. We cannot afford to destroy habitats, especially before we’ve even discovered the species they support or understand the role they play in our oceans ecosystem.
1. Goblin Shark — the “living fossil” finally seen in the wild
Credit: Mistukurina Owstoni.
One of the ocean’s most unusual inhabitants, the goblin shark is the only surviving member of a shark lineage dating back approximately 125 million years. It has changed remarkably little since the age of the dinosaurs. Its long, flattened snout is packed with sensory organs that detect the weak electrical signals produced by prey in the darkness of the deep sea. When prey comes within reach, the goblin shark launches its highly extendable jaws forward in a split second—one of the fastest feeding mechanisms of any shark.
They inhabit deep waters, typically between 300 and 2000 metres, where sunlight never reaches. Because they live so far below the surface, most of what scientists know has come from individuals accidentally caught by deep-sea fishing vessels. Their true behaviour in the wild remained a mystery for decades. That changed in 2026, when scientists published the first-ever live observations of goblin sharks in their natural habitat. Using remotely operated vehicles and deep-sea cameras, researchers documented two individuals near Jarvis Island and the Tonga Trench.
2. Frilled Shark — the snake-like shark from Earth’s past
Credit: Johannes-Maria Schlorke, Deutsches Meeresmuseum.
One of the ocean’s most ancient and mysterious predators, looking much as it did when its lineage first appeared around 150 million years ago. With its long, eel-like body, six pairs of frilled gill slits, and more than 300 needle-like teeth, it resembles a creature from the age of dinosaurs more than a modern shark. Living primarily between 500 and 1,500 metres below the surface, where sunlight never reaches, the frilled shark is thought to hunt by lunging at squid, fish, and other sharks with its flexible jaws and backward-pointing teeth, but much of its behaviour remains a mystery because it is so rarely observed in the wild. Researchers believe it may have one of the longest gestation periods of any vertebrate—up to three and a half years—but even this remains difficult to confirm.
3. Viper Dogfish
Credit: Dr. Stephen M. Kajiura.
Nicknamed the “vampire shark,” the viper dogfish looks like something straight out of a horror movie. Reaching just about 50 centimetres (20 inches) in length, this elusive deep-sea shark has an unusually slender body, glowing eyes, and oversized, needle-like fangs that protrude even when its mouth is closed. Living hundreds of metres below the surface—typically between 270 and 1,000 metres—it spends its life in the perpetual darkness of the deep ocean. Like many deep-sea sharks, the viper dogfish possesses bioluminescent organs called photophores on its underside that produce a faint glow, helping it blend into the dim light filtering down from above in a form of camouflage known as counterillumination. Scientists believe this adaptation helps conceal the shark from predators and prey alike. Because so few individuals have ever been observed alive, much of its behaviour remains a mystery, but researchers think its enormous fang-like teeth and highly extendable jaws allow it to snatch fast-moving fish and squid in the darkness.
4. Cookiecutter Shark —bites perfect circles out of whales
Photo: NOAA’s Fisheries Collection.
Don’t let its small size fool you—the cookiecutter shark is one of the ocean’s most unusual predators. Growing to less than 60 centimetres (2 feet) in length, this deep-sea shark has developed one of the strangest feeding strategies in the animal kingdom. Rather than chasing and overpowering prey, it attaches itself to much larger animals using its thick, suction-like lips before rotating its body to carve out a perfectly round plug of flesh with its razor-sharp lower teeth. The distinctive wounds it leaves behind have been found on whales, dolphins, seals, tuna, billfish, and other sharks. Surprisingly, cookiecutter sharks have also left their unmistakable circular bite marks on submarines, underwater cables, and oceanographic equipment, prompting engineers to redesign protective coatings for some underwater technology. Living mostly between 1,000 and 3,500 metres during the day before migrating closer to the surface at night to feed, the cookiecutter shark remains rarely seen by people despite occurring in tropical and subtropical oceans around the world.
5. Pocket Shark — glows and has “pockets”
Credit: Mark Grace, NOAA.
The pocket shark is one of the rarest and most mysterious sharks on Earth. Measuring less than 15 centimetres (6 inches) in length, only a handful of specimens have ever been documented, making it one of the least-studied shark groups known to science. Its name comes from a pair of unusual pocket-like glands located just behind its pectoral fins. Scientists believe these specialized organs secrete bioluminescent fluid, allowing the shark to produce light—possibly to communicate, distract predators, or attract prey, although their exact function remains unknown. There have been only two confirmed encounters with this shark, the first species, Mollisquama parini, was described from a single specimen collected off the coast of Chile in 1979, while a second species, Mollisquama mississippiensis, wasn’t discovered until 2010 in the Gulf of Mexico.
6. Greenland Shark — the Ancient Arctic giant
Greenland shark surfacing in Tremblay Sound, Nunavut and in the depths of the St. Lawrence Estuary (Canada). Photos: Eric Ste-Marie and © Doug Perrine.
The Greenland shark is one of the most extraordinary vertebrates on Earth, whale sharks are known to live to 150 years, but scientists estimate that some can live to over 250 years, making them the longest-lived known vertebrates. Growing at an incredibly slow rate of less than one centimetre per year, these gentle giants can take around 150 years to reach sexual maturity, making their populations particularly vulnerable to overfishing and other human impacts. Greenland sharks inhabit the icy waters of the North Atlantic and Arctic Oceans, where temperatures often remain close to freezing year-round. Their slow metabolism and unique physiological adaptations—including natural compounds in their tissues that help them function in frigid conditions—allow them to thrive in an environment where few other large predators can survive. As climate change rapidly transforms the polar oceans, researchers are working to better understand and protect one of the planet’s most long-lived marine predators.
7. Tasselled Wobbegong — the Camouflage Master
Credit: Tom Fisk/Pexels.
The tasselled wobbegong is a master of disguise, so perfectly adapted to life on coral reefs that it often resembles a patch of seaweed or coral more than a shark. Found in the shallow tropical waters of northern Australia, New Guinea, and nearby islands, this carpet shark is covered in intricate patterns and elaborate skin flaps around its head, making it almost invisible against the reef. Rather than pursuing prey, the tasselled wobbegong relies on patience and camouflage, lying motionless until an unsuspecting fish or crustacean comes within striking distance before launching a rapid ambush. Its remarkable appearance and hunting strategy demonstrate just how diverse shark evolution has become over millions of years. Far from the sleek, fast-swimming predators often portrayed in popular culture, the tasselled wobbegong is a reminder that sharks have evolved an astonishing variety of shapes, behaviours, and survival strategies to thrive in habitats ranging from coral reefs to the deepest parts of the ocean.
8. Megamouth Shark
The megamouth shark (Megachasma pelagios) is one of the world’s rarest and most mysterious shark species. Discovered only in 1976, it was completely unknown to science until an individual became entangled in a U.S. Navy ship’s anchor. Unlike the fast-swimming predators many people associate with sharks, the megamouth is a slow-moving filter feeder that swims with its enormous mouth open to capture tiny shrimp-like krill, jellyfish, and plankton. It can grow to around 5–7 metres (16–23 feet) in length and inhabits deep ocean waters, typically rising closer to the surface at night to feed. One of the megamouth shark’s most remarkable features is the bright, silvery band lining its upper jaw. Rather than producing its own light, this reflective strip bounces back the faint glow of bioluminescent organisms in the deep sea. Scientists believe it may act as a lure, attracting krill and other small prey toward the shark’s enormous open mouth, helping it feed more efficiently in the darkness.
- The Most Recently Discovered Shark: Dudgeon’s walking shark
Credit: Mark Erdmann.
In June 2026, researchers discovered Dudgeon’s walking shark in a shallow reef in Milne Bay, Papua New Guinea. No it does not have two legs to ‘go where the people are’, but walking sharks use their muscular pectoral and pelvic fins to “walk” across the seafloor in search of small fish and invertebrates. This allows them to navigate reef crevices and even survive for short periods in shallow, low-oxygen pools. Not only is this shark adorable, they have a unique pattern of dashes and dots.
- Error Seamount catshark (Bythaelurus stewarti)
Credit: Simon Weigmann, Carina Julia Kaschner, Ralf Thiel.
In 2018, scientists honored Rob Stewart’s extraordinary contribution to shark conservation by naming a newly discovered species after him. Found in the deep waters of the Nazca Ridge in the southeastern Pacific Ocean at depths of around 380–420 metres (1,250–1,380 feet), this elusive catshark lives far beyond the reach of most divers. The researchers dedicated the species to Rob because he “inspired the second author and stimulated her interest in sharks,” recognizing the profound influence his films and conservation work had on a new generation of shark scientists. It is a lasting tribute—ensuring that Rob’s name will forever be part of the scientific record of the animals he devoted his life to protecting.
-Maggie Kendall
