50 Fun Facts About Hard Sharks

Roughly how many teeth can a shark shed over its lifetime?

The teeth sit in the gums, not the jaw, and rows move forward like a conveyor belt.

How many gill slits do sharks have on each side of the body?

Sharks also have a ribless skeleton of cartilage and pectoral fins that are not fused to the head.

Across how many orders are the more than 500 living shark species divided?

Some of those orders are extinct; the ground sharks alone include the requiem sharks, catsharks and hammerheads.

The oldest total-group chondrichthyans, the spiny sharks or acanthodians, appeared in which period?

That is around 439 million years ago; shark-like scales go back even further, to the Late Ordovician.

Cladoselache, an early shark, is famous for well-preserved fossils from which formation?

Oddly, no claspers have ever been found on it, unlike its close relatives.

Helicoprion, a Permian shark relative, is famous for what bizarre feature?

Alexander Karpinsky named it in 1899 from Russian and Australian fossils; the name means spiral saw.

Megalodon's jaws could exert a bite force of roughly what?

It lived from about 23 to 3.58 million years ago and its name simply means big tooth.

Pliny the Elder described fossil megalodon teeth in AD 73 as what?

The so-called glossopetrae were later worn as amulets and used as tableware supposedly able to detect poison.

Which Italian physician first described sharks' electroreceptive pores in 1679, without knowing what they did?

The mucus-filled pores detect electric fields, but that was not proven until the 20th century.

What is the maximum known length of the dwarf lanternshark, the world's smallest shark?

It is known only from the upper continental slopes off Colombia and Venezuela, at 283 to 439 metres down.

What is the largest reliably recorded length for a whale shark?

That is 61.7 feet, and its lifespan is estimated at 80 to 130 years.

The whale shark was first scientifically distinguished after a specimen was harpooned in 1828 where?

Military doctor Andrew Smith described it the following year.

Roughly how many rows of tiny teeth can a whale shark's mouth contain?

It also has 20 filter pads, and each shark's spot pattern is unique like a fingerprint.

Which is the second-largest living shark after the whale shark?

Its name comes from its habit of feeding at the surface as if sunbathing, using bristle-like gill rakers to catch plankton.

The first megamouth shark ever seen was caught in November 1976 when it became tangled in what?

It happened off Kahuku, Hawaii, and fewer than 300 specimens have been recorded since.

What top speed can the shortfin mako, the fastest shark, reach in bursts?

Its genus name Isurus means equal tail, from the near-equal lobes of its caudal fin.

How far up the Mississippi River has a bull shark been recorded?

Bull sharks tolerate fresh water but are not true river sharks like the genus Glyphis.

By what alternative name is the bull shark known in Africa?

In Central America it is the Lake Nicaragua shark, and it thrives in warm, shallow, brackish water.

Which shark ranks second only to the great white in recorded fatal attacks on humans?

It is also nicknamed the garbage eater for the licence plates and tyres found in its stomach.

Of 500-plus shark species, how many have double-digit tallies of fatal unprovoked attacks?

The great white, tiger and bull; worldwide there are only around 80 unprovoked attacks a year.

One study found great white shark stomach temperatures of 24.7-26.8 °C in water of what temperature?

That heat lets them stay active in cold water and launch full breaches at Cape fur seals from 20 metres down.

Who coined the great white's genus name Carcharodon in 1838?

It combines two Greek words meaning sharp and tooth, and the great white is the only living species in the genus.

The largest preserved great white is a 5.83 m female caught in 1956. Which city displays it?

Her estimated weight was 2,000 kg; a 5.94 m shark from Ledge Point, Western Australia, is the largest reliably measured.

What is the technical name for the flattened, T-shaped head of a hammerhead shark?

It gives binocular vision and more room for electroreceptors, and hammerheads unusually school by day and hunt alone at night.

The bonnethead was the first shark found to be omnivorous. What plant makes up about 62% of its gut contents?

The whale shark was the second omnivorous species found; the bonnethead is also the only shark with head shape differing between sexes.

Which deep-sea shark, described in 1898, has pink skin and highly protrusible jaws?

Its lineage is some 125 million years old, and its long snout is covered in ampullae of Lorenzini.

The frilled shark's gestation period can last how long?

It swallows prey whole with 300 recurved needle-like teeth and moves like an eel.

The epaulette shark can survive complete lack of oxygen for how long?

It copes with night-time hypoxia in tide pools by boosting blood flow to the brain, and it walks on its paired fins rather than swimming.

What is the deepest-living species known, recorded down to 3,675 m?

Its eyes are tuned to spot the bioluminescence of prey, since sunlight never reaches that depth.

Which is the largest luminous vertebrate on record?

Most are 1 to 1.4 m long, with a maximum reported length of possibly 1.8 m.

Cookiecutter bite marks have been found on which unusual man-made objects?

The little cigar-shaped shark gouges round plugs from whales, fish and, occasionally, people.

The word wobbegong is thought to come from Dharug, an Australian Aboriginal language, and means what?

It refers to the fleshy growths around the carpet shark's mouth; there are 12 species.

Thresher sharks use their tails, which can be as long as their bodies, to do what?

The common thresher is also called the fox shark, from its Latin name Alopias vulpinus.

Which is the only shark known to gulp air at the surface and store it in its stomach for buoyancy?

Its embryos also practise intrauterine cannibalism, the most developed one eating its siblings in the womb.

Zebra sharks get their name from their juvenile pattern. What do adults look like?

Young ones under about 50 to 90 cm have light vertical stripes on brown, which is why they are also called Indo-Pacific leopard sharks.

Blue sharks are noted for large litters. Roughly how many pups can one produce?

They average about 3.1 m and migrate huge distances, such as New England to South America.

Spiny dogfish have one of the longest gestations of any animal. How long?

They defend themselves with two mildly venomous spines in front of the dorsal fins.

Squalene, used in cosmetics and vaccine adjuvants, takes its name from which shark genus?

It was first extracted from shark liver oil, and conservationists worried in 2020 about sharks being killed for COVID-19 vaccines.

Pilot fish accompany many sharks but prefer which species?

They eat parasites and leftovers from their host, and juveniles hang around jellyfish instead.

Angelsharks of the genus Squatina are so flattened that they resemble what?

They are ambush predators that lie buried on the bottom, and many species are now critically endangered.

How many species of sawshark are there in the order Pristiophoriformes?

They slash prey with a tooth-edged rostrum and are most common from the Indian Ocean to the southern Pacific.

Ningaloo Reef, famous for whale shark aggregations, is how long?

It is Australia's largest fringing reef and the only large reef so close to a landmass, and became a World Heritage Site in 2011.

Studies estimate roughly how many sharks are killed for their fins every year?

Demand rose sharply after 1997, driven by shark fin soup and traditional cures.

Jaws was shot mostly on location on which island, becoming the first major film shot on the ocean?

The mechanical sharks kept breaking, so Spielberg hid the shark and leaned on John Williams's two-note theme.

Who rewrote the Jaws script during filming after Peter Benchley's first drafts?

The film starred Roy Scheider, Richard Dreyfuss and Robert Shaw and became the prototype summer blockbuster.

Discovery Channel's Shark Week premiered in which year?

Tom Golden created it, and it first aired on July 17.

Chondrichthyes splits into Elasmobranchii and which subclass, the chimaeras or ghost sharks?

Chimaeras have been proposed as their own class entirely; the elasmobranchs lack the gill covers bony fish have.

The Devonian-Carboniferous shark relative Stethacanthus had a back fin shaped like what?

Only mature males carried the strange spine-topped fin, which died out around 299 million years ago.

Remoras cling to sharks using a sucker formed from which modified fin?

Sliding backward tightens the grip; swimming forward releases it.

At roughly what age does a Greenland shark, the longest-lived vertebrate, reach sexual maturity?

Its lifespan is estimated at 272 to 510 years, and its gestation may last 8 to 18 years.