Sharks have a reputation for being some of the most fearsome predators in the ocean. The sight of a great white’s gaping maw has haunted many nightmares. However, there are some shark species that are so strange it’s hard to believe they’re real. The first evidence of sharks in the fossil record dates back 450 million years. Over this vast timespan, sharks have developed adaptations that are not only intriguing but also just plain weird. Keep reading to discover eight bizarre sharks you won’t believe actually exist.
Goblin Shark

Goblin sharks can extend their entire jawbone forward to ambush fast-moving prey.
©Dianne J. Bray Museums Victoria / CC BY 3.0 AU – Original / License
Little is known about the aptly-named goblin shark (Mitsukurina owstoni). This strange species of deep-sea shark lives along continental shelves in the Atlantic, Pacific, and Indian Oceans at depths of around 800-4,265 feet. While the maximum size of goblin sharks is still unknown, scientists estimate they can reach 18-20 feet in length. The goblin shark rarely comes into contact with humans in such deep water, and there have been no recorded fatal goblin shark attacks. Its long, narrow teeth indicate the goblin shark feeds on softer prey such as fish, shrimp, octopus, and squid.
Goblin sharks have a high concentration of electrosensors, known as ampullae of Lorenzini, in their noses. This organ allows them to detect the electrical fields of hidden prey. To catch their prey, these sharks have the bizarre ability to catapult their entire jawbone forward, using ligaments in their mandibular joints like rubber bands. This extends the range of their bite. A thick cartilage structure on the floor of their mouths, called the basihyal, also drops down to expand the size of their mouths. Goblin sharks swim slowly to conserve energy in the cold water, so these adaptations allow them to strike quickly to catch agile prey.
Greenland Shark

The Greenland shark has a lifespan of at least 400 years.
With a maximum length of 24 feet and weights of up to 2,200 pounds, Greenland sharks (Somniosus microcephalus) are among the largest sharks in the world. These sharks typically inhabit the Northern Atlantic and Arctic regions from the surface to depths of over 7,200 feet. Greenland sharks are not considered a danger to humans, as they live in cold waters where people rarely go. They eat a broad range of prey, including squid, fish, seals, and other sharks. Some dissected sharks have even contained the remains of mammals like reindeer and horses.
What makes this shark so unusual is its incredible lifespan. Researchers have found that the Greenland shark is the longest-lived vertebrate, estimated to reach at least 400 years old. Scientists previously believed the shark’s cold habitat and slow metabolism were responsible for its long lifespan. However, the shark’s DNA may hold the key. A study led by the University of Tokyo found that the shark has genes that help control inflammation and support the immune system. Additional research has found that the shark has multiple copies of genes involved in DNA repair, which also likely contribute to the shark’s longevity.
Frilled Shark

Frilled sharks have six gills, whereas most other sharks only have five.
©Citron / CC-BY-SA-3.0 / Wikimedia Commons – Original / License
With its long, slender body and snake-like head, the frilled shark (Chlamydoselachus anguineus) looks more like an eel than a shark. It gets its name from the six gills on the sides of its neck, which give it the odd appearance of wearing a frilled collar. The frilled shark can reach 6.6 feet in length and weigh up to around 200 pounds. This shark can be found on continental shelves in the Atlantic, Pacific, and Indian Oceans, primarily inhabiting depths from around 300-4,900 feet. These rarely seen sharks prefer deep, cold waters where humans are unlikely to be found, so they pose no threat to people.
The shark’s sharp, rear-facing, three-pronged teeth suggest its primary foods are small fish and squid, which are easily snagged on its specialized teeth. Since these sharks are commonly found on the ocean floor, they may eat carrion as well. Frilled sharks also have long, extremely flexible jaws that are believed to allow them to swallow prey up to half their size whole. Some authors have suggested the prehistoric-looking frilled shark may even be the explanation behind sea serpent sightings.
Bahamas Sawshark

Sawsharks use their saw-like snouts to slash and stun fish and sift through the sediment for prey.
©Arzi/Shutterstock.com
Bahamas sawsharks (Pristiophorus schroederi) inhabit the waters of the western Atlantic Ocean, primarily off the coasts of Florida, Cuba, and the Bahamas. They prefer sandy and muddy areas near continental slopes and coral reefs at depths of around 1,300-3,200 feet. These sharks grow to about 2.8 feet in length, but weight data on these rare sharks is currently unknown. Living near the ocean floor, they rarely come into contact with humans and are believed to be harmless.
The shark’s elongated, saw-like snout, or rostrum, is one-third the length of its body. It is bordered by sharp, tooth-like projections called rostral teeth, which are actually modified scales rather than true teeth. Scientists believe the sharks use their rostrums for capturing prey and possibly for self-defense. Their rostrums are covered with ampullae of Lorenzini, which allow them to detect electrical signals of potential prey. Sawsharks swing their rostrums from side to side, striking and stunning fish or forcing crustaceans and other bottom-dwelling invertebrates from their hiding places in the sediment.
Viper Dogfish

The viper dogfish extends its jaws and impales prey on its needle-like teeth.
This strange-looking shark is the viper dogfish (Trigonognathus kabeyai), which inhabits the Pacific Ocean near the coasts of Hawaii, Japan, and Taiwan. These elusive sharks migrate vertically, swimming at depths of over 1,000 feet at night and around 500 feet during the day. Viper dogfish are small sharks, reaching only about 21 inches long and weighing around 1.7 pounds. As they typically swim deep in the ocean and are very rarely seen, they are not known to be dangerous.
Viper dogfish have light-producing cells on their skin, called photophores. These cells emit light, which may aid the shark in hunting prey, attracting mates, and confusing predators. The sharks have triangular jaws with rows of needle-like teeth. They primarily eat small fish, but they are also capable of consuming prey up to half their own size. In the stomach contents of research specimens, prey fish have been found nearly intact, with only puncture wounds. Like the goblin shark, the viper dogfish has extendable jaws. It is also believed to be a lunge feeder, thrusting its jawbones forward to catch rapidly moving prey.
Swell Shark

Swell sharks can nearly double in size by swallowing water or air.
©iStock.com/Natalie Ruffing
The swell shark (Cephaloscyllium ventriosum) can be found in the eastern Pacific Ocean from the coasts of California down to Chile. They are most commonly seen at depths of around 3-120 feet, but they have been observed at depths up to 1,500 feet. The shark can grow to a maximum of 3.5 feet in length with an average weight of around 15 pounds. Scientists believe this slow-moving, nocturnal shark mainly eats diurnal fish and crustaceans that are less active at night. The swell shark is not a danger to humans and only becomes aggressive if harassed.
Swell sharks are unique in their ability to swallow water or air to escape predators. If attacked, the shark hides in rocks and crevices, swallowing water to expand its stomach. The shark has sphincter muscles at each end of its stomach, which trap the water. By swelling to nearly twice its normal size, the swell shark makes itself too large to be pulled out of its hiding place. In open water, the shark grabs its tail in its mouth before filling its stomach with water, making its body difficult for predators to bite. Out of water, the shark gulps air and swells up like a balloon.
Tasselled Wobbegong

The tasselled wobbegong can dislocate its jaws to swallow large prey.
©frantisekhojdysz/Shutterstock.com
The tasselled wobbegong (Eucrossorhinus dasypogon) lives in coral reefs in the tropical regions of the southwest Pacific. They typically inhabit shallow water at depths up to 160 feet. This shark is part of the carpet shark family, named for their wide, flat bodies and their habit of lying camouflaged on the seafloor. Tasselled wobbegongs reach a maximum length of about 4 feet and a weight of up to about 33 pounds. These sharks are generally not considered dangerous, but they may bite if provoked. However, there have been no documented fatal attacks on humans.
This shark is a popular attraction in aquariums due to its unusual appearance. Tasselled wobbegongs have a fringe of skin flaps beginning at the pectoral fins and running along the front of their flat heads. This forms a lacy beard which helps disguise its mouth. The shark lies motionless on the seafloor until prey such as fish, squid, octopus, crabs, and other sharks swim within striking distance. They lunge forward and suck the prey into their open mouths, often swallowing it whole. They also have the ability to dislocate their jaws to ingest larger prey.
Basking Shark

Basking sharks can open their mouths up to 3.5 feet wide.
©Martin Prochazkacz/Shutterstock.com
At lengths of up to 40 feet and weighing upwards of 10,000 pounds, it comes as no surprise that the basking shark (Cetorhinus maximus) is the second-largest shark in the ocean. They can be found in temperate waters in both the Northern and Southern hemispheres. Basking sharks are generally observed close to the surface. However, some sharks have been documented at depths of nearly 5,000 feet. Incredibly, basking sharks can also breach, hurling their 5-ton bodies completely out of the water as high and as fast as great whites. These gentle giants are harmless, but they should be given space due to their remarkable size.
Basking sharks are filter-feeders, but they do not actively suck in water. These sharks swim at a speed of around 2mph with their mouths open up to 3.5 feet wide. They take in about 2,000 tons of water each hour, filtering out zooplankton using their gill rakers. Gill rakers are bony projections that trap zooplankton and prevent them from escaping through the gills. Basking sharks also migrate depending on the availability of plankton. Little is known about their migration routes, but one female basking shark was tracked traveling nearly 6,000 miles across the Atlantic.
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