107 Fun Facts About Sharks

Which sensory organs let sharks detect the weak electric fields given off by other animals?

Ampullae of Lorenzini open as small dark pores around the snout and lead to jelly-filled canals that pick up the faint electricity of a prey animal's muscles, even when it lies buried.

Roughly how long do scientists estimate a Greenland shark can live?

About 400 years: carbon-dating proteins in the eye lens put one five-metre female at 272 to 512 years old, so even the low figure makes the Greenland shark the longest-lived animal with a backbone.

What is the primary material that makes up a shark's skeleton?

Cartilage, the same gristly tissue as the tip of a human nose, is about half as dense as bone, so a shark's skeleton is light and helps keep it from sinking.

What term describes sharks that lay eggs?

Oviparous sharks lay their eggs in tough protective cases and then leave them; the embryo lives on its yolk and hatches with no parental care at all.

What is a baby shark called?

Pup is the name for a young shark, whether it hatches from a leathery egg case or is born live, as the young of many species are after hatching inside the mother.

What is the primary threat to most shark populations worldwide?

Overfishing, driven by demand for shark fins and meat, is identified as the biggest threat to shark populations, often exacerbated by their slow reproductive rates.

Young lemon sharks spend their first years sheltering in which habitat?

Mangrove shallows serve as the lemon shark's nursery: females return there to give birth, and the young stay for several years, sheltered from larger predators.

What is the name for the small, tooth-like scales that cover a shark's skin?

Shark skin is covered in placoid scales, also known as dermal denticles, which give it a rough, sandpaper-like texture and help reduce drag while swimming.

Which sensory structure lets a shark feel vibrations and pressure changes in the surrounding water?

The lateral line system is a row of fluid-filled canals along each flank whose hair cells register water movement, letting a shark home in on the vibrations of struggling prey.

What is the scientific name of the great white shark?

Carcharodon carcharias is the great white, the only living species of its genus; despite the name, only its underside is white, while its back is grey to almost black.

How do sharks typically maintain buoyancy without a swim bladder?

A large, oil-filled liver does the job: its oils are less dense than seawater, so together with a light skeleton they give the lift that a swim bladder gives bony fishes.

Which of these shark species is considered the fastest?

Shortfin mako shark: its bursts are put at around 70 km/h, over 40 mph, and anglers know it for leaping high out of the water when hooked, now and then landing in the boat.

What are the leathery egg cases of some sharks and skates commonly called?

Mermaid's purse is the beachcomber's name for the tough capsule that shelters a shark or skate embryo for months; empty ones are often found washed up on beaches.

Which fish hitches rides on sharks using a suction disc on top of its head?

Remora: its first dorsal fin has become a slatted sucker on top of the head, letting it clamp onto a shark and be carried wherever its host swims.

The basking shark's common name comes from its habit of doing what?

Feeding at the surface with its huge mouth agape, the basking shark cruises so slowly that it seems to be lazing in the warm upper water, which is how it got its name.

What is it called when sharks continuously replace lost teeth?

Polyphyodonty is the lifelong replacement of teeth, set after set, as in sharks and crocodiles; mammals such as humans are the main exception, with just two sets.

Which deep-sea shark is often referred to as a 'living fossil' due to its primitive, eel-like appearance?

The frilled shark, one of the most primitive sharks alive, pairs its eel-like body with some 300 needle-sharp, backward-curving teeth, thought to snag the squid and small fish it eats.

A 1992 book that fuelled sales of shark supplements popularised the myth that sharks are immune to which disease?

Cancer: Sharks Don't Get Cancer built a market for pills of powdered shark skeleton, yet tumours, some of them malignant, have been found in sharks, and clinical trials showed the pills did nothing.

What is the function of the spiracle in some shark species?

Drawing in water to breathe: the spiracle is a small opening just behind each eye that keeps water flowing to the gills even while a shark's mouth is busy with a meal.

What term describes a shark's tail fin with its longer upper lobe?

Heterocercal: the backbone turns upward into the longer top lobe of the tail, as in sharks and sturgeons; a homocercal tail, by contrast, looks symmetrical.

What do anglers call the mix of ground-up fish and blood tipped overboard to attract sharks?

Chum is bait of ground-up oily fish scattered on the water; it works well enough on sharks that some US states ban chumming close to the beach for the safety of bathers.

Which shark species gulps air at the surface and stores it in its stomach to hang motionless while hunting?

Sand tiger shark: denser than water and lacking a swim bladder, it swallows air at the surface and holds it in its stomach, which lets it hover almost motionless as it stalks fish.

What is the trance-like state a shark enters when turned upside down?

Tonic immobility: turned on its back and held there, a shark goes limp and still, a reflex researchers use to handle sharks and sawfish safely while they tag them.

Which structure do tiger and blue sharks slide over their eyes when biting?

Nictitating membrane: this tough third eyelid slides across the eye of a tiger or blue shark as it bites; great whites lack one and roll their eyes back instead.

Which sharks are famous for gathering in schools that can number in the hundreds?

Hammerheads of the scalloped species gather in schools that can number in the hundreds, a habit that lets fishing boats take whole groups at once and has helped make it critically endangered.

Which swimwear brand marketed its 'Fastskin' racing suits as mimicking shark skin?

Speedo: when a Harvard lab tested the fabric in 2012, its shark-inspired surface did nothing to cut drag, though real shark skin did.

What is the scientific term for a hammerhead shark's flattened head?

Cephalofoil is the term for the hammerhead's wing-like head, which gives room for extra electrosensory pores across its underside and is thought to improve the depth perception of its widely spaced eyes.

Which fin is missing in many sharks, including the dogfishes and angel sharks?

The anal fin is absent in the dogfishes, angel sharks and sawsharks alike, so checking for it quickly narrows down which order an unfamiliar shark belongs to.

The name 'mako' was borrowed into English from which language?

Māori gave English the word: 'mako' can mean either the shark or one of its teeth, which were prized and worn as ornaments.

What does the name megalodon literally mean?

Big tooth: the name joins Greek roots for 'big' and 'tooth', apt for an animal known mostly from its fossil teeth, the largest of them close to 18 centimetres long.

Which specialized organs do male sharks use for internal fertilization?

Claspers are a pair of rods formed from the male's pelvic fins that channel sperm into the female; in many species they carry hooks or spines that may hold them in place during mating.

Which Australian state began a drum-line 'shark control' programme in 1962?

Queensland: its Shark Control Program has set nets and baited drum lines off popular beaches from 1962, a cull that has also killed dolphins and endangered hammerhead sharks.

A shark's upper jaw hangs beneath, rather than fusing to, which structure?

The cranium: because the upper jaw is not fused to the skull, a shark can push it outward, away from the head, as it bites into prey.

Which shark has been found far up both the Amazon and the Mississippi?

Bull shark: it can adjust its salt balance for fresh water, and a population in Lake Nicaragua was once thought to be landlocked until it was shown to reach the sea by river.

What is the term for the light that lanternsharks produce from tiny organs in their skin?

Bioluminescence is light made by a chemical reaction inside the body; these deep-sea sharks glow from the belly, probably as camouflage against predators looking up from below.

Which reflective layer behind the retina helps sharks see in dim light?

Tapetum lucidum: a mirror-like layer of guanine crystals behind the shark's retina bounces light back through the photoreceptors, the same structure that makes a cat's eyes shine in headlights.

Survivors of which US Navy cruiser, torpedoed in July 1945, drifted for days among sharks?

USS Indianapolis had just delivered components of the atomic bomb; of about 900 men who went into the water, only 316 were saved after days of exposure, thirst and shark attacks.

The bonnethead, the first shark shown to be omnivorous, eats large amounts of what?

Seagrass can make up more than half of its gut contents, and it digests the stuff rather than just passing it through.

Roughly how many species of shark have scientists described?

About 500: just over 500 living species are known, and for all the group's reputation only a few of the larger ones are dangerous to people.

Which network has aired Shark Week every summer since 1988?

Discovery Channel first ran Shark Week in July 1988; the ten-show block was a hit, and its early years were devoted to conservation and to correcting misconceptions about sharks.

After laying its auger-shaped egg cases, what does a female horn shark do with them?

Wedges each into a rock crevice: the two spiral flanges around the case let the mother jam it tight into a crack, where predators cannot easily pull it out before it hatches.

What hard material primarily makes up a shark's tooth?

Dentin makes up the bulk of each tooth; the glossy outer cap is not true enamel but enameloid, a tissue that is probably closer kin to dentin itself.

Which New England island stood in for Amity Island in the filming of Jaws?

Martha's Vineyard hosted the shoot, where the mechanical sharks kept failing in the open sea, so Spielberg mostly hinted at the shark instead of showing it.

Which surfer lost her left arm to a shark at 13 and was back on her board within a month?

Bethany Hamilton was attacked while surfing off Kauai in 2003; she taught herself to ride with one arm and went on to compete as a professional surfer.

The spiny dogfish can arch its back to stab a captor with dorsal spines that secrete what?

A mild venom: small glands sit beside the sharp spine in front of each dorsal fin, and the shark curls into a bow to drive one in, leaving a painful wound for a careless fisher.

Some sharks lose roughly how many teeth over a lifetime?

About 30,000: some sharks shed and replace tens of thousands of teeth in a lifetime, with replacements growing in a groove inside the jaw and moving forward like a conveyor belt.

Which instrument plays the solo theme for the shark in John Williams's score for Jaws?

Tuba: Tommy Johnson played the shark's theme as a solo written in an extremely high range for the instrument, one of more than 2,000 film soundtracks he performed on.

What keeps a shark's blood in osmotic balance with seawater?

A high concentration of urea in the blood and tissues makes a shark's body fluids about as concentrated as seawater, so it does not steadily lose water to the sea the way marine bony fishes do.

The zebra shark is named for a striped pattern seen only in which individuals?

Juveniles: young zebra sharks are dark with pale stripes, while adults are spotted, which is why the same species is also called the leopard shark in parts of the Indo-Pacific.

At its quickest, roughly how often does a shark replace each tooth?

Every week or so: the quickest sharks renew a tooth in little more than a week while others take months, and because cold water slows the process, teeth are replaced faster in summer than in winter.

Jacques Cousteau described which species as 'the most dangerous of all sharks'?

Oceanic whitetip: Cousteau called it 'the most dangerous of all sharks'; slow-moving but bold, it is often the first shark to reach survivors of ships and planes lost far out at sea.

Which actor battles a giant megalodon in the 2018 film The Meg?

Jason Statham, himself a former competitive diver, plays rescue diver Jonas Taylor, whose team meets a 75-foot megalodon during a mission on the floor of the Pacific.

Which marine mammal preys on great white sharks, sometimes flipping them upside down?

Orca: killer whales have been recorded killing great whites off South Africa, turning the shark belly up to subdue it and often eating little but its liver.

Sawsharks differ from the look-alike sawfishes in having a pair of what halfway along the snout?

Barbels: the whisker-like pair hangs from the sawshark's toothed snout; sawfishes lack them and are not sharks at all but rays, with their gill slits underneath rather than on the sides.

Roughly how long does a spiny dogfish carry her young, one of the longest pregnancies of any vertebrate?

About 2 years: gestation runs 18 to 24 months and ends in a litter of only about six, which leaves heavily fished spiny dogfish stocks slow to rebuild.

Sharks, rays and skates belong to which class of fish?

Chondrichthyes: the class is well over 400 million years old, and because its members' skeletons rarely fossilise, the earliest ones are known mostly from scattered scales and teeth.

The jet-black 'ninja lanternshark', described in 2015, was named after which author?

Peter Benchley: the species name benchleyi honours the Jaws author, who came to regret the fear his novel stirred up and spent his later years campaigning for ocean conservation.

Which of these shark species is known for its distinctive long, whip-like tail, often used to stun prey?

Thresher shark: its scythe-like tail can be as long as the rest of its body, and divers have filmed it whipping the tail overhead into a shoal, stunning more than one sardine with a single slap.

What is the term for a female shark giving birth with no genetic contribution from a male?

Parthenogenesis: when a bonnethead in a Nebraska zoo tank that held no males gave birth, DNA tests showed the newborn had no father, the first proof of a 'virgin birth' in any shark.

Which dimly lit ocean layer, nicknamed the twilight zone, is home to many deep-sea sharks?

Mesopelagic: in this layer, roughly 200 to 1,000 metres down, lanternsharks light up their bellies to match the faint glow from above, hiding their silhouettes from predators below.

What is it called when sharks must swim continuously to force water over their gills?

Ram ventilation: a few fast-swimming species have lost the ability to pump water across their gills at rest, so one that is held still would be expected to suffocate.

What was rough sharkskin, once used as sandpaper and sword-grip covering, called?

Shagreen is untanned shark or ray skin whose tooth-like denticles make it abrasive and hard-wearing; Japanese swordsmiths wrapped katana hilts in it and cabinetmakers used it to smooth wood.

Which flat-bodied sharks, often mistaken for rays, lie buried in sand to ambush passing fish?

Angel sharks: they lie hidden under the sand by day and lunge upward at fish that pass overhead, yet their thick, tube-shaped tails mark them as true sharks.

Which shark is an obligate suction feeder, generating some of the strongest suction measured in any aquatic vertebrate?

Nurse shark: it generates some of the strongest suction pressures measured in any aquatic vertebrate, hoovering prey out of crevices at night, then spends the day resting in piles with others of its kind.

In 2025, which US state recorded more shark bites than any other?

Florida: it had 11 of the country's 25 unprovoked bites in 2025, leading the nation as it usually does, yet none of them was fatal, while California's five included the year's one US death.

Which shark's indiscriminate appetite has earned it the nickname "garbage can of the sea"?

Tiger shark: a generalist that takes seabirds, dolphins and other sharks, it also swallows rubbish dumped at sea, so metal, plastic and even licence plates have turned up in its stomach.

Researchers tell individual whale sharks apart using what feature?

Their spot patterns: the pale spots behind the gills form an arrangement unique to each whale shark, and photo-identification software adapted from star-mapping algorithms matches them like fingerprints.

Spearfisher Rodney Fox, nearly killed by a great white in 1963, went on to spend decades doing what?

Running shark cage dives: inspired by a visit to a zoo, he helped develop the observation cage in the late 1960s and has since taken film crews and divers to meet the species that mauled him.

Wobbegongs belong to which family group of sharks?

Carpet sharks: wobbegongs belong to the order Orectolobiformes, whose bold, symmetrical markings resemble a woven rug and hide them on the seabed; the group also includes nurse, zebra and whale sharks.

Which shark is the second-largest living fish?

Basking shark: second only to one other species, it has fooled people even in death, as when a rotting carcass netted by a Japanese trawler in 1977 was hailed as a plesiosaur before tests pointed to this shark.

In which US state did the deadly 1916 shark attacks often linked to the novel Jaws take place?

New Jersey: sharks killed four people along its shore and in Matawan Creek in twelve days of July 1916; writers often call the panic an inspiration for Jaws, though the novel grew from a giant shark caught off Montauk.

Which aquarium displayed a young great white for a record 198 days before releasing her back to the sea?

Monterey Bay Aquarium: no captive great white had lasted beyond 16 days, but this young female fed and grew there from September 2004 until she began hunting her tank-mates and was returned to the wild.

A 2014 study showed white sharks can live past 70 by dating their vertebrae with carbon left by what?

Cold War nuclear tests: bomb blasts spiked the ocean's carbon-14, time-stamping the growth bands and revealing a 73-year-old male, when earlier band counts had suggested no more than 23 years.

Fossil shark teeth were long called glossopetrae, a Greek-derived name meaning what?

Tongue stones: people took the triangular fossils for the petrified tongues of snakes or dragons, a belief Nicolas Steno's 1667 study of a shark's head helped overturn.

Despite being one of the most abundant open-ocean sharks, the blue shark was given which global Red List status in 2019?

Near Threatened: the listing reflects fishing pressure, since huge numbers of blue sharks are hooked or netted every year as bycatch by boats that are after other fish.

What is unusual about the goblin shark's jaws?

They shoot forward to grab prey: stretched ligaments fling the jaws out at about 3 metres per second, to nearly a tenth of the shark's body length, the fastest and longest jaw thrust measured in any shark.

Roughly how long does a cookiecutter shark grow?

Around 50 cm: males top out near 42 cm and females near 56 cm, which makes the cookiecutter's habit of biting chunks out of whales and tuna all the more improbable.

The first megamouth shark ever caught, in 1976, was taken off which US state?

Hawaii: the first megamouth was hauled up in November 1976 by a US Navy vessel about 25 miles off Oahu, tangled in a sea anchor, and the species had been completely unknown until that moment.

In most United States waters, what management designation does the white shark carry?

A prohibited species: no US fishery may keep a white shark, so one hooked by accident, whether by an angler or a commercial boat, has to be released immediately.

Megalodon is thought to have died out roughly how long ago?

About 3.6 million years: a 2019 review of well-dated fossil beds found the younger teeth were reworked from older rock or of doubtful origin, moving megalodon's extinction a million years earlier than thought.

Which country's 100-peso banknote shows a whale shark, known locally as the butanding?

Philippines: the note pairs the butanding with Mayon Volcano, and the law backs up the tribute, making snorkellers keep their distance and punishing anyone who touches the animals.

Which US beach town is nicknamed the 'shark attack capital of the world'?

New Smyrna Beach: the nickname is earned, since the county around it logged six shark bites in 2025 alone, over half its state's total, and that was a quiet year against a recent average of ten.

Which pungent Icelandic delicacy is Greenland shark, fermented and hung for months to make it safe to eat?

Hákarl: fresh Greenland shark is loaded with trimethylamine oxide and poisons anyone who eats it, so the meat is fermented and then hung to dry for four to five months.

Chimaeras, the sharks' deep-sea cousins with grinding tooth plates, are also known as what?

Ghost sharks: chimaeras are not true sharks, having a single covered gill opening on each side, and the males carry a club-like organ on the forehead for holding a mate.

Which small shark can haul itself out of the water to reach isolated tide pools?

Epaulette shark: this small reef shark pushes off the bottom with paddle-shaped pectoral and pelvic fins in a gait that looks unmistakably like walking, and it survives hours of low oxygen in isolated tide pools.

What term, from the Greek for 'brother-eating', describes a sand tiger embryo devouring its siblings in the womb?

Adelphophagy: the most developed embryo in each of the sand tiger's two uteri eats its smaller siblings and then the remaining eggs, so usually only two young are born.

How many gill slits do most shark species typically have on each side of their head?

5: sharks have no bony gill cover of the kind most other fish have, so each of the five slits opens straight to the sea, though a few species carry six or seven.

How do white sharks keep their swimming muscles warmer than the surrounding sea?

A counter-current heat exchanger: warm blood leaving the muscles hands its heat to cold blood coming in, which keeps the white shark a faster, more active hunter in cool seas that slow other fish.

Which parasite commonly attaches to the eyes of Greenland sharks?

A copepod: the crustacean Ommatokoita elongata anchors itself to the Greenland shark's cornea and impairs its sight, though the shark is thought not to need keen eyes in the dark Arctic depths.

Sharks, with a fossil record reaching back some 450 million years, appeared before which of these?

Trees: the oldest shark-like scales are about 450 million years old, while the first trees arose roughly 400 million years ago, and sharks have since come through all five mass extinctions.

What term describes sharks, notably Great Whites, leaping entirely out of the water?

Breaching: off South Africa, great whites hunting Cape fur seals strike so fast that shark and seal often burst clear of the water together.

What colour pattern, dark above and pale below, camouflages most sharks?

Countershading: a dark back seen from above blends into the deep, while a pale belly seen from below blends into the bright surface, hiding sharks from prey and predators in both directions.

What are the stiff horizontal ridges on the tail base of mako and white sharks called?

Caudal keels: lamnid sharks such as the mako and white shark carry a stiff horizontal keel on each side of the tail base, stabilising the narrow peduncle that powers their crescent-shaped tails.

Before the word 'shark' took hold in English in the 16th century, what did sailors call the animals?

Sea dogs: mariners used the name until 'shark', a word of uncertain origin, displaced it, and the dogfishes still carry the dog in their name.

Which treaty lists the great white shark in its Appendix II to keep international trade in check?

CITES, the Convention on International Trade in Endangered Species, demands export permits for Appendix II species, and in 2025 its members went further, voting to ban commercial trade in whale sharks outright.

Which oil, now used in moisturisers and vaccines, takes its name from the Latin name of a genus of sharks?

Squalene: a Japanese chemist first isolated it from deep-sea sharks in 1906, but nearly all plants and animals make some, human skin included, so olive oil can supply it instead.

What gives the goblin shark its pinkish colour?

Blood vessels showing through its skin: the skin is semi-translucent, so a ghostly white youngster turns pinker as it ages, then fades to brown once a specimen is preserved.

What structure inside a shark's short intestine boosts the surface that absorbs nutrients?

Spiral valve: coiled like a corkscrew, it makes up for an intestine far shorter than a mammal's, at the cost of slowing a meal's passage through the gut.

Which extinct shark relative carried a buzz-saw whorl of teeth in its lower jaw?

Helicoprion: this Permian fish carried a spiral of teeth in its lower jaw like a circular saw; 2013 CT scans showed the whorl sat inside the jaw and that it was closer to the chimaeras than to true sharks.

Which shark with a long, blade-like snout is the only living member of the family Mitsukurinidae?

Goblin shark: the family name honours Kakichi Mitsukuri, the Tokyo zoologist who passed the first specimen, caught off Japan, to the American who described it in 1898.

A great white tagged off South Africa stunned scientists by swimming to which country and back in under nine months?

Australia: the female's 20,000-kilometre round trip was the fastest ocean-crossing return migration then known in any swimming animal, and it overturned the belief that female great whites stay near home.

What adaptation lets the cookiecutter shark cut neat circular plugs of flesh from its prey?

Suction lips, saw-like teeth: it seals its fleshy lips onto the victim, anchors with narrow upper teeth and twists so its interlocking lower teeth saw out a plug; it has bitten whales, dolphins and even submarine sonar domes.

A dead shark gradually starts to smell strongly of what?

Ammonia: the smell builds as the carcass decomposes and the nitrogen-rich compounds held in shark flesh break down, which is why cooks soak the meat in lemon juice, vinegar or milk.

What sense do sharks mainly use to detect prey, such as blood in the water, from long distances?

Smell: a shark steers toward a scent by noting which nostril the odour reaches first and turning to that side.

Below roughly what depth are sharks almost entirely absent from the ocean?

3,000 m: a 2006 survey of trawl, hook and camera records found sharks all but missing from the abyss, which leaves about 70% of the ocean to bony fishes, perhaps because so little food reaches that deep.

What nickname did the Jaws film crew give their temperamental mechanical shark?

Bruce: the crew named all three full-size props after Steven Spielberg's lawyer, Bruce Ramer, and they kept failing at sea as salt water got into their air hoses and corroded their skin.

The slow-moving Greenland shark belongs to which family, known as the sleeper sharks?

Somniosidae: the name fits, since the Greenland shark cruises at little more than a kilometre an hour, yet seals turn up in its stomach, so it is thought to creep up on them while they sleep.