The Weirdest Shark Traits Ever

By AT&T Digital Media Productions editorial team

 

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Why does a hammerhead have a hammer head? Why is a thresher shark’s tail so long? And what’s a wobbegong? Over time, sharks have developed some pretty incredible (and weird) specializations. Here’s a rundown of which sharks rock the craziest physical characteristics--and why.

 

SUPER-SENSOR: HAMMERHEAD SHARK

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Most people recognize the hammerhead shark’s signature silhouette. With two lobes that protrude from either side of the head like axe blades, its design is seriously unique. Useful, too: the shape of a hammerhead may help it maneuver and stay afloat, and the lobes are full of sense receptors that help track prey.

Hammerheads are the least buoyant sharks, and researchers believe that they depend on their heads to stay swimming. Their heads are hydrodynamic, with rounded tops and flattened edges (similar in cross-section to an airplane wing), providing buoyancy and “lift” as the sharks cruise along.

These sharks’ heads are also packed with sense receptors. Their eyes and nostrils are far apart, at either end of the head, which allows them to see and sample a wider area of water. They also have tiny electromagnetic sensors, called ampullae of Lorenzini, scattered across their heads. These pores respond to the weak electrical aura emanating from every living creature, helping the sharks locate food. You may have seen a hammerhead swinging its head from side to side while swimming—this “minesweeper” motion is how it hunts hidden prey on the ocean floor.

 

WATER FILTER: BASKING SHARK

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My, what a big mouth you have! The basking shark, along with the megamouth shark and whale shark, is a filter feeder. Instead of biting and swallowing its food, it drifts gently along, passively but continuously pulling plankton-rich water into its vast maw and out its gills. It’s the world’s second-largest fish (coming in just behind the whale shark), but it’s harmless to humans, feeding only on microorganisms.

Basking sharks hang out near the ocean’s surface, but they’re not really sunbathing: the warm upper region of the ocean is where their food supply of zooplankton is most populous. A basking shark’s massive gills strain up to 2,000 tons of water per hour, filtering small crustaceans, invertebrates, fish eggs, and larvae. Every so often, it gives its gills a little flutter, probably to clear out and swallow accumulated food.

 

CLEAN GETAWAY: COOKIE CUTTER SHARK

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The cookie cutter shark, or cigar shark, is a species of dogfish with a very special method of feeding. It doesn’t attack directly or tear its victims to death. Instead, it extracts neat, circular plugs of flesh from larger animals with its distinctive bite. It moves quickly, first ambushing and attaching itself to a victim with its suction lips, then using its upper teeth as anchors while the lower row slices out a piece of meat. Like a melon baller, but for marine life.

No need to waste time and energy subduing prey. The cookie cutter shark just grabs a bite to go and saves the rest for later. This technically makes it a parasite, not a predator—like a big, extra-painful leech.

Telltale circular bite scars have been found on nearly every species of large marine animal in the cookie cutter’s range, including dolphins, whales, seals, stingrays, bony fish, and other sharks—the cookie cutter can take chunks out of blue sharks, basking sharks, and great white sharks, to name a few.

 

WHIPLASH: THRESHER SHARK

 

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The upper half of a thresher shark’s tail fin is as long as the rest of its whole body, making it easy to recognize. The common thresher shark preys on schools of small fish, like mackerels, herrings, and sardines. It uses its whiplike tail as, well, a whip; like an Old West cattleman, it cracks its tail at groups of fish so that they gather in a smaller area and move in the desired direction. It then uses its tail to whack and stun prey before eating it.

Thresher sharks sometimes hunt in small packs, a useful technique for surrounding fish schools.

 

DIFFERENT TEETH: HORN SHARK

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Horn sharks are bottom-feeders, sucking up crustaceans, sea urchins, and shellfish. Their scientific name, Heterodontus, means “different teeth,” referring to their dual types of choppers: sharper teeth in the front for grabbing, and flat molarlike teeth in the back for crushing and grinding.

Horn sharks inhabit shallow waters offshore, at the murky bases of kelp beds, and stay near the bottom. They aren’t great at swimming in open water, but they have strong pectoral fins, which they can use to crawl around instead. You may have seen these sharks’ spiral-shaped egg sacs washed up on shore, where beachcombers refer to them as “mermaids’ purses.”

 

LIVING CARPET: WOBBEGONG SHARK

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Is that a shark, or a shag rug? The wobbegong shark is flat, with beardlike protrusions along the edge of its head. It sports a fetching pattern of leopard spots, which camouflage the shark as it lies completely still in wait for prey. When it notices a tasty-looking small fish, it lunges to grab the target with its sharp teeth.

The name “wobbegong” is believed to come from an Australian Aboriginal word for “shaggy beard.” The wobbegong’s beard is comprised of sensors, like the whiskers of a catfish. This shaggy fringe also helps it blend in among mud, coral, and undersea plants while it waits to execute an ambush.

The 12 species of wobbegong are collectively known as carpet sharks, for obvious reasons. Though they’re not overtly dangerous to humans, they will bite if grabbed (or, more commonly, stepped on).

 

To see even more unbelievable sharks, watch Shark Week, only on Discovery.

 

Sources: Elasmo Research, Florida Museum, Monterey Bay Aquarium, Discovery