40 Fun Facts About Basking Shark

A 2018 study found that the slow, plankton-eating basking shark can leap from the sea as fast as which predator?

Great white breaches are no faster: a tagged basking shark shot up from 28 metres with ten beats of its tail and left the sea at about 18 kilometres an hour. One scientist likened it to finding that cows are as fast as wolves.

Reflecting its slow, passive lifestyle, the basking shark has the smallest what, weight for weight, of any shark?

Brain power matters little to a fish that feeds by cruising open-mouthed through clouds of plankton, with no prey to stalk, chase or outwit.

A rotting basking shark hauled up by a Japanese trawler off New Zealand in 1977 was first hailed as which reptile?

Plesiosaur fever swept Japan after the crew sketched the carcass and dumped it overboard. A decaying basking shark sheds its lower jaw early, leaving a small skull on what looks like a long neck.

Which organ runs the length of a basking shark's body cavity, can reach a quarter of its weight and keeps it buoyant?

Its liver is packed with oil lighter than seawater, so the organ acts as a built-in float and doubles as a long-term energy store.

In the 1950s Canada's fisheries department fitted a patrol boat with what to kill basking sharks off British Columbia?

A sharpened bow blade let the Comox Post slice through sharks that had been tangling in salmon nets, and it logged 413 kills in 14 years. The steel knife now sits in a museum in Port Alberni.

Unlike 99.9% of fish, basking sharks were found in 2023 to keep their core swimming muscles at what temperature?

Warmer than the water is how tuna and other fast hunters run their muscles, so finding the trait in a plankton grazer stunned researchers. One compared it to discovering that cows have wings.

Lines of basking sharks cruising nose to tail at the surface are thought to explain many old sightings of what?

Sea serpents were a common verdict when sailors watched basking sharks swimming in single file, and washed-up carcasses with oddly small skulls kept the legend alive.

Among all the fish alive today, where does the plankton-eating basking shark rank by size?

Second largest, behind only the whale shark: a typical adult basking shark is about 7.9 metres long and weighs more than 4.5 tonnes.

So little is known about basking shark births that science has only ever recorded a single what?

Pregnant female basking sharks are almost never met: the only one on record was carrying six young. Pups are thought to be born already 1.5 to 2 metres long.

A basking shark eats only plankton, yet its jaws hold hundreds of teeth; what are they like?

Small and hooked, each one is just 5 to 6 millimetres long, and a single row can hold about a hundred of them.

Only three sharks live on plankton: the basking shark, the whale shark and which rarely seen fish found in 1976?

Megamouth sharks were unknown until one tangled in a US Navy ship's sea anchor off Hawaii. It is the smallest of the three plankton eaters, at around 4 to 5.5 metres long.

Which dark, bristle-like structures in a basking shark's throat strain plankton from the water flowing through?

Gill rakers do for this fish what baleen does for a filter-feeding whale. The water escapes through slits that almost ring the shark's head, while the food stays behind.

Basking sharks seek out dense patches of which tiny crustaceans, their favourite kind of zooplankton?

Copepods of the genus Calanus are the prize: water sampled beside feeding basking sharks held far more of them, and bigger ones, than water a short distance away.

A basking shark is a ram feeder, meaning it can only push water through its mouth by doing what?

Moving forwards is its only option: a whale shark can also suck or pump water in, but a basking shark that stops travelling stops eating.

Before satellite tags proved them active all year, basking sharks were thought to spend winter doing what in deep water?

Hibernating seemed a fair guess because the sharks vanish from the surface each autumn. Tags showed they simply go deep, sometimes 900 metres down, and keep on feeding.

Groups of basking sharks that gather in summer and swim in slow, tight circles are thought to be doing what?

Courting is the leading explanation for the rings, which form where plankton is thickest. Basking sharks live mostly alone or in single-sex shoals, so such gatherings may be how mates meet.

A basking shark that swam 9,589 km across the Atlantic to Newfoundland had been tagged in 2007 off which island?

Isle of Man waters are a summer hotspot, and this journey was the first proof that European and American basking sharks can mix. On the way the shark dived to 1,264 metres.

Islanders on Atlantic coasts once harpooned basking sharks mainly for oil that was burned in what?

Lamps were lit with basking shark oil long before electricity, and a single fish could yield 200 to 400 gallons of it. The oil was also used to lubricate machinery.

Which author of the otter memoir Ring of Bright Water first tried his luck harpooning basking sharks from Soay?

Gavin Maxwell bought the island of Soay, off Skye, in the 1940s and built a shark oil factory there. The business failed within three years, and he told the story in Harpoon at a Venture.

Which marine mammals have been seen feeding on basking sharks off both California and New Zealand?

Orcas are among the very few predators a basking shark has. The scars many of the sharks carry may come from far smaller attackers, such as cookiecutter sharks.

A basking shark tagged off Cape Cod surprised scientists by spending a month near the mouth of which river?

Amazon waters were the last place anyone expected to find the species. The tagged fish crossed the equator out of sight, staying 200 to 1,000 metres down for weeks on end.

Tagged basking sharks that summer off western Scotland have wintered as far south as which archipelago?

The Canaries were only half the journey: the same individual sharks came back to the waters around Coll and Tiree in consecutive summers.

The longest basking shark on record, 12.27 metres, was trapped in a herring net in 1851 off which part of Canada?

Bay of Fundy fishermen landed a giant whose weight was later put at 16 tonnes. A later growth study suggested that basking sharks much over 10 metres are unlikely.

Basking shark oil is rich in which compound, now used in skin creams and some vaccine adjuvants?

Squalene takes its name from Squalus, a genus of sharks, because shark oil is where a Japanese chemist first found it in 1906. Olive oil contains it too.

After the oil trade faded, basking sharks were still hunted because their fins fetched high prices for making what?

Soup thickened with shark fin is a prestige dish in East Asia, and the basking shark's fins are so big that a fresh pair has fetched up to $1,000 at market.

Which 1934 film about Atlantic islanders staged a basking shark hunt its cast had to be taught how to carry out?

Man of Aran gives much of its second half to the hunt, though director Robert Flaherty admitted the sequence was there for the box office. A stuffed basking shark went on show in London for the premiere.

Keem Bay, once home to a basking shark fishery, lies on which part of County Mayo seen in The Banshees of Inisherin?

Achill was once known for its shark fishing, a business run industrially by the 1950s with the oil as the prize. Keem is now a Blue Flag beach.

Johan Ernst Gunnerus, who gave the basking shark its first scientific description in 1765, held which post in Norway?

Bishop of Nidaros, based in Trondheim, Gunnerus gathered specimens on his travels around Norway and named the shark Squalus maximus. The plant genus Gunnera honours him.

Which nickname does the basking shark share with Mola mola, a heavy bony fish that also lolls at the surface?

Sunfish, like the official name, comes from the shark's habit of lying at the surface as if sunning itself. Another old name for it is the bone shark.

Before birth, basking shark embryos are thought to use their teeth to feed on what inside the mother?

Unfertilised eggs keep arriving from the mother as food, a habit called oophagy. It may explain why a plankton eater bothers to grow teeth at all.

Which parasitic fish are often seen clinging to basking sharks, though they probably cannot pierce the thick skin?

Sea lampreys cannot bite through the armoured hide, but they may irritate the shark enough to make it leap from the sea or rub itself against the bottom.

A basking shark's skin can graze a diver who brushes against it because it is covered in what?

Tooth-shaped scales called dermal denticles armour every shark, and the basking shark's are notably large. A layer of slime sits over them.

The Stronsay Beast of 1808, a 'sea monster' later judged to be a rotting basking shark, washed ashore in which islands?

Orkney's carcass was measured at 55 feet and declared a new species by Edinburgh naturalists. A London anatomist ruled that it was a decayed basking shark of about 30 feet.

Basking sharks are found around the world, but in which kind of water do they spend most of their time?

Cool temperate seas of about 8 to 14.5 °C suit them best. They do cross the tropics, but hundreds of metres below the sunlit surface.

Which part of a basking shark is conical in adults but long and distinctly hook-like in the young?

Its snout is thought to help a pup feed, in the womb and just after birth, by steering more water into the mouth.

For reasons unknown, only the right one of which paired organs seems to work in basking sharks that carry young?

Ovaries on the left seem to do nothing at all, and with so few breeding animals ever examined, nobody can yet say why.

On the IUCN Red List, which category has the slow-breeding, once heavily hunted basking shark been placed in?

Endangered reflects how slowly the species bounces back: a basking shark takes many years to mature and is thought to breed only once every two to four years.

Which country, whose Malin Head is a noted basking shark hotspot, gave the species legal protection only in 2022?

Ireland acted long after its neighbours: basking sharks in Scottish waters have had full legal protection since 1998.

Opened wide to feed, a basking shark's cavernous jaw can measure roughly how far across?

1 metre of gape is why even a modest five-metre shark is reckoned to sieve up to 450 tonnes of seawater an hour.

Trade in basking shark fins and other parts is restricted in many countries under which wildlife treaty?

CITES places the basking shark on Appendix II, so its parts may be traded only with records showing the catch was sustainable. Britain led the push for the listing.