92 Fun Facts About Dolphins

What makes up the bulk of most dolphins' diet?

Fish and squid make up most dolphins' diet; a group will herd a school into a tight 'bait ball' and take turns charging through it.

Which of these senses are dolphins thought to lack altogether?

Smell is the missing sense: dolphins have neither olfactory nerves nor the brain lobes that process scent, so they are thought unable to smell at all.

Which dolphin, the only cetacean endemic to New Zealand, is also among the smallest?

Hector's dolphin lives only in New Zealand's coastal waters, and keeping so close to shore puts it in the path of fishing nets: entanglement in gillnets is the greatest threat to it.

What is the thick layer of insulating fat under a dolphin's skin called?

Blubber does more than keep a dolphin warm: it stores energy for lean times and smooths the body's outline, which makes swimming more efficient.

What is a typical group of dolphins called?

A pod can merge with others where food is plentiful: common dolphins sometimes gather in 'mega-pods' of thousands of animals.

What is the dolphin's sonar-like way of finding prey in murky water called?

Echolocation means sending out sound pulses and reading the echoes, which a dolphin is thought to pick up through its jaw: fat in the lower jaw carries the sound to the ears.

Which fatty organ in a dolphin's forehead focuses its sound pulses into a beam?

The melon is built of fats of differing density, so it bends sound much as a glass lens bends light and focuses the pulses made in the nasal passages into a forward beam.

What sounds do dolphins fire off in rapid 'trains' to scan murky water for prey?

Clicks are made in the nasal passages, not with vocal cords: air pushed past the 'phonic lips' makes the tissue vibrate, and a rapid series is called a click train.

A dolphin's conical teeth are built for what job?

Seizing fast-moving prey is all the teeth do: a dolphin grips a fish and swallows it whole, head first, so the spines don't catch in its throat.

How often can a bottlenose dolphin's outermost skin layer be replaced?

A bottlenose dolphin's outermost skin layer can be replaced every 2 hours, about nine times faster than human skin; the constant sloughing is thought to keep the surface smooth and cut drag.

Female orcas are among the few animals, besides humans, known to live for decades after what?

Menopause comes at about 40 for female orcas, which can then live for decades; the long afterlife pays off, since a post-breeding mother raises her grown sons' odds of survival.

What is a dolphin's dorsal fin made of?

Fibrous connective tissue, with no bone or cartilage, makes up the dorsal fin and the tail flukes alike; only the flippers hold bones, the same set found in a human arm.

How do dolphins manage to sleep without drowning?

They rest one brain half at a time: the half that stays awake keeps a dolphin rising to breathe and watching for predators while the other sleeps.

Shark Bay bottlenose dolphins in Australia teach their young to wear what while foraging?

Shark Bay dolphins wear marine sponges on their beaks to protect them while rooting for fish on the seabed; the habit is learned, passed mostly from mother to daughter, a clear case of animal culture.

The boto, a river dolphin that hunts among the trees of flooded rainforest, lives in which region?

South America's boto swims into flooded forest in the wet season; unlike sea dolphins it has unfused neck bones, so it can turn its head 90 degrees to steer between the trunks.

The word 'dolphin' comes from the Greek delphís, related to a Greek word meaning what?

Womb is delphys in Greek; the name is often read as 'a fish with a womb', though it may instead describe the animal's shape.

Dolphins belong to which branch of the whales?

Toothed whales take in every dolphin, along with the sperm whale; their cousins the baleen whales gave up teeth for comb-like plates that strain food from the water.

What are the closest living relatives of dolphins and other cetaceans?

Hippopotamuses were long grouped with pigs on the evidence of their teeth, until blood-protein and DNA studies showed their nearest living kin are the whales and dolphins.

The orca and other dolphins that are commonly called whales share which collective name?

Blackfish is an old name for these dark-skinned dolphins, and the 2013 documentary Blackfish borrowed it for the story of Tilikum, a captive orca.

Unlike most other mammals, dolphin calves are usually born in what way?

Tail first is the usual delivery, though head-first births are also seen; among bottlenose dolphins another adult, nicknamed an auntie, sometimes stays close to the mother and her newborn.

Orcas are sometimes called the 'wolves of the sea' because of how they do what?

Hunt in packs is the reason: orcas work together to corner prey, at times taking whales larger than themselves, and nothing in the sea preys on them.

In Peru, dolphin meat is sold under the name chancho marino, meaning what?

Chancho marino, 'sea pork', is the euphemism under which dolphin meat is sold in Peru, even though the animals are protected by law there.

Bottlenose dolphins are known to have 'signature' versions of what, unique to each individual?

Signature whistles work like names: each bottlenose dolphin develops its own, and wild dolphins call back when they hear a copy of theirs but ignore copies of others'.

Male river dolphins in Brazil have been observed using weeds and sticks for what purpose?

Adult males carry sticks, branches and lumps of clay in their jaws as a sexual display aimed at females; researchers found the showing-off went hand in hand with fights between the males.

The baiji, a river dolphin declared functionally extinct in 2006, lived in which river?

The Yangtze was the baiji's only home; a six-week search in 2006 found none, and its loss is blamed chiefly on fishing gear and heavy shipping.

The Amazon river dolphin is famous for turning what colour as an adult, especially in males?

Pink is the adult colour, and males are pinkest; it has been put down to skin abraded in fights, though water temperature and clarity may also play a part.

Which fish, common on restaurant menus, is also called the dolphinfish despite being no relation?

Mahi-mahi, a Hawaiian name borrowed into English in the 1940s, is what the fish is called on a plate; its older English name was simply 'dolphin', hence the confusion.

Pelorus Jack, a dolphin protected by New Zealand law in 1904, was famous for doing what?

Escorting ships through the Marlborough Sounds for 24 years made Pelorus Jack, a Risso's dolphin, a celebrity; the government stepped in after someone was reported to have shot at him from a passing ship.

Feeding wild dolphins is illegal in US waters, largely because of what effect on the animals?

Teaches them to beg: fed dolphins lose their wariness of people and boats and start taking bait off fishing gear, so the Marine Mammal Protection Act's rules class feeding as an illegal 'take'.

Which orca ecotype of the northeast Pacific hunts seals and sea lions rather than fish?

Transient, or Bigg's, orcas hunt marine mammals in small groups and avoid the fish-eating orcas that share their waters; the two types are not known to interbreed.

What is the term for a dolphin rising vertically to hold its head above the surface?

Spyhopping lets a dolphin or whale hold its head clear of the water to view its surroundings; Antarctic orcas do it to look for seals resting on ice floes.

In some coastal areas, bottlenose dolphins cooperate with local fishermen by doing what?

In Laguna, Brazil, bottlenose dolphins cooperate by driving fish into their nets: they herd mullet towards the shore and signal the moment to cast, then feed on fish that scatter as the nets fall.

Indohyus, a fox-sized land relative of the first whales, had unusually dense limb bones that helped it do what?

Stay underwater: the heavy bones worked as ballast, and Indohyus is thought to have dived to hide from predators, much as the African water chevrotain does today.

Orcas flip great white sharks onto their backs to induce a paralysis called what?

Tonic immobility is a trance-like paralysis a shark enters when turned belly-up; orcas exploit it to subdue great whites, and a South African pair became known for cutting out the livers.

Which salmon, also known as king salmon, makes up most of the diet of the northeast Pacific's fish-eating orcas?

Chinook, the largest Pacific salmon, is these orcas' preferred prey, so the decline of Chinook runs is counted among the chief threats to the endangered southern population.

Off Península Valdés in Argentina, orcas hunt sea lions using what technique?

Deliberately beaching themselves lets the orcas grab sea lions in the surf before wriggling back to sea; stranding is usually fatal to cetaceans, so the young need years of practice.

Orca family groups are matrilines built around whom?

The eldest female anchors the group: her sons and daughters alike stay with her for life, so a matriline can hold several generations travelling together.

What is it called when dolphins surf the pressure wave pushed ahead of a moving ship?

Bow-riding lets dolphins surf the pressure wave a moving hull pushes ahead of it, travelling faster for less effort; they also ride ocean swells and the wake behind a boat.

The long-finned pilot whale, a large dolphin, was found in 2014 to have about twice as many neocortical neurons as what?

A human has about half the pilot whale's 37 billion neocortical neurons; the study's authors concluded that neuron numbers alone cannot explain human abilities.

In Louis Herman's experiments, the bottlenose dolphin Akeakamai learned to understand what?

Akeakamai learned a human sign language of hand and arm gestures invented by Herman's team; her tank-mate Phoenix learned an acoustic version, and both understood sentences such as 'touch the frisbee with your tail'.

The grindadráp, a centuries-old community drive hunt of pilot whales, is a tradition of which islands?

The Faroe Islands have eaten pilot whale since the Viking age; records of the hunt go back to 1584, and the catch is shared out among the community by custom.

What does the spinner dolphin do as it leaps from the water, earning its name?

Rotating around its long axis, a spinner can turn several times in one leap; the splashdown is thought to work as a signal to other dolphins, and may also shake off clinging remoras.

In local folklore, the Amazon river dolphin is said to come ashore at night in what form?

A handsome young man is the dolphin's disguise in the tales: he charms the young women of the villages after dark, then slips back to the river before morning.

Two small rod-shaped bones near the tail of a modern dolphin's skeleton are thought to be remnants of what?

Hind limbs dwindled to these jointless pelvic splints after the ancestors of whales and dolphins, four-legged land mammals that were probably good runners, took to the water.

Which god is often shown riding a dolphin in Roman art and later European painting?

Cupid rides a dolphin beside the leg of the Augustus of Prima Porta statue, a nod to the emperor's claimed descent from Venus, Cupid's mother.

In Hindu mythology, the susu, a South Asian river dolphin, is linked to which deity?

Ganga, deity of the Ganges, is said to have had her descent heralded by the dolphin, and her mount, the Makara, is sometimes drawn as a dolphin.

Billie, a wild dolphin from Adelaide's Port River, picked up which trick while housed with trained dolphins?

Tail-walking spread from Billie to other wild dolphins after her release in 1988, then died away: a fad with no known use, most likely passed on by imitation.

Ambulocetus, an early whale known from fossils found in Pakistan, has a Latin name meaning what?

Walking whale joins the Latin for 'to walk' and 'whale'; in the water the animal is thought to have swum much as an otter does, by flexing its spine up and down.

In Greek myth, which god boarded a Cretan ship in the form of a dolphin to recruit its crew as priests?

Apollo steered the ship to the shore below Delphi, where the sailors became priests of his oracle and worshipped him as Apollo Delphinios, 'of the dolphin'.

The hourglass dolphin was accepted as a species in 1824 based solely on what?

A drawing and witness accounts were all Quoy and Gaimard had to go on when they named it; the dolphin keeps to cold open water around Antarctica and is rarely seen near shore.

Commerson's dolphin is nicknamed after which other black-and-white animal?

Commerson's dolphin is nicknamed the panda dolphin for its sharply divided black-and-white pattern, which has also earned it the names skunk dolphin and piebald dolphin; Philibert Commerson recorded it in the Strait of Magellan.

The critically endangered Māui dolphin survives only off the west coast of what?

New Zealand's North Island is Te Ika-a-Māui in Māori, which is where the dolphin gets its name; a 2021 government estimate put the whole population at about 54 animals.

Which country has named the susu, a freshwater river dolphin, its National Aquatic Animal?

India made the susu a national symbol; the dolphin itself is all but blind, with tiny eyes that lack a lens, and finds its way through muddy water without sight.

The Indus river dolphin, which is nearly blind, is known for swimming in what unusual way?

On its side is how this dolphin often swims, probing the river bottom for food with its long beak; dams and irrigation barrages have since cut its population into isolated groups.

The franciscana, or La Plata dolphin, is the only river dolphin that lives where?

In coastal ocean waters and salty estuaries off Argentina and Uruguay, the franciscana is a river dolphin by family ties only: it is the one member of its group that has not kept to fresh water.

DNA suggests the Clymene dolphin arose as a natural hybrid of the striped dolphin and which relative?

Spinner dolphin ancestry shows in the Clymene's habits: it too spins as it leaps, which is why older books call it the short-snouted spinner dolphin.

The Irrawaddy dolphin takes its name from a river in which country?

Myanmar's Irrawaddy River gave the dolphin its name, though it also lives along coasts and in other rivers of southern Asia; it is known for spitting jets of water, perhaps to herd fish.

A dolphin's dark back and pale belly are an example of which kind of camouflage?

Countershading works both ways: seen from above, the dark back merges with the depths, and from below the pale belly blends with the bright surface, hiding a dolphin from predators and prey alike.

Winter, the bottlenose dolphin who inspired the film Dolphin Tale, was famous for having what, after a crab-trap injury?

A prosthetic tail was made for Winter by a firm that fits human limbs, after a crab-trap line cost her her own as a calf in 2005; without it she swam with a fish-like side-to-side beat, so she wore it mainly for therapy.

In the 2011 film Dolphin Tale, who plays Dr. Cameron McCarthy, the specialist who comes to Winter's aid?

Morgan Freeman plays Dr. McCarthy opposite an unusual co-star: the real Winter, who appears as herself in the film.

The Cove, about the Taiji dolphin hunt, hid its cameras inside fake versions of what?

Rocks hid the high-definition cameras: director Louie Psihoyos, a former National Geographic photographer, filmed in secret through 2007 with a camouflaged crew on the headlands above the cove.

Taiji, the whaling town whose annual dolphin drive hunt was exposed in The Cove, is in which country?

Japan's Taiji, in Wakayama Prefecture, has been a whaling town since the 1600s; after the film drew the world's attention, the country's aquariums agreed in 2015 to stop buying dolphins from the hunt.

In marine engineering, what is a 'dolphin'?

In marine engineering a dolphin is a group of pilings used for mooring, driven into the seabed as a berthing point or a fender that protects docks and bridge piers from ships.

Lolita, also called Tokitae, was an orca displayed for over 50 years at which aquarium?

Lolita lived at the Miami Seaquarium from 1970, when she was captured from the southern resident population at Penn Cove, until her death from renal failure in August 2023, as plans were made to return her to the Salish Sea.

The US Navy Marine Mammal Program, whose dolphins hunt mines, is based in which city?

The Navy Marine Mammal Program is based at Point Loma in San Diego, training bottlenose dolphins and California sea lions to find mines and intruders; its teams deployed in the Vietnam and Iraq wars.

Which title did the heir to the French throne hold from 1350 to 1791?

Dauphin means 'dolphin': the lords of Viennois bore one on their coat of arms and took the word as a title, and when the last of them gave up his lands to France in 1349, the title went to the king's heir.

Ecco the Dolphin, the 1992 underwater adventure game, was published by which company?

Sega published Ecco the Dolphin for the Mega Drive/Genesis in 1992; it was created by Ed Annunziata at Sega and developed by the Hungarian studio Novotrade, later renamed Appaloosa Interactive.

Swimming's first limit on underwater dolphin kicking followed a 1988 Olympic final in which stroke?

Backstroke finalists in Seoul kicked beneath the surface for so much of the 100 metres that the sport's governing body voted straight after the Games to cap the underwater phase; butterfly swimmers now face a limit too.

The best-known wholphins are fertile hybrids of a bottlenose dolphin and which other species?

False killer whale and bottlenose dolphin share a count of 44 chromosomes, which lets their offspring breed in turn; Kekaimalu, born at Hawaii's Sea Life Park in 1985, grew up to have calves of her own.

Heaviside's dolphin is endemic to the Benguela ecosystem off the coast of which continent?

Africa's south-west coast is its only home, in the cold Benguela Current; the name is a slip, as the first specimen was brought to Britain by a Captain Haviside and credited by mistake to a surgeon called Heaviside.

The black dolphin lives only along one country's coast, from Valparaíso south towards Cape Horn; which country?

Chile is the only home of the black dolphin, better known as the Chilean dolphin; fishermen once killed it for bait to catch king crab, a practice that is now illegal.

Fraser's dolphin was named in 1956 from what, picked up on a Borneo beach?

A single skull, found in Sarawak in 1895, lay in the British Museum for decades before Francis Fraser named the species from it; nobody recorded the living animal until 1971.

The genus name Steno, for the rough-toothed dolphin, comes from the Greek for what?

Narrow is the meaning of the Greek stenos, the root of 'stenosis', a narrowing; in the dolphin's case it describes the long, slender beak.

Peale's dolphin, a cold-water species also called the black-chinned dolphin, lives around which place?

Tierra del Fuego and the Falklands are its home waters, where it keeps close to shore and likes to thread the channels through beds of kelp.

Right whale dolphins of the genus Lissodelphis are distinctive for lacking what?

A dorsal fin is missing in both species, as it is in the right whales, which may be how these dolphins got their name; the northern one is the only finless dolphin in the North Pacific.

Spinner dolphins rest in shallow bays by day and head offshore at night to do what?

Foraging fills the night because that is when their prey comes within reach: the small animals they eat live hundreds of feet down by day and move upward after dark.

Atlantic spotted dolphin calves are born plain and gain their first spots around what stage of life?

Weaning is roughly when the first spots show; until then a calf can pass for a slim bottlenose, and the spots go on darkening and spreading as it ages.

Millions of pantropical spotted dolphins died in the 1960s-70s in which fishing gear?

Tuna purse seines were set around dolphin schools on purpose in the eastern Pacific, killing millions; dolphin-friendly fishing methods adopted from the 1980s cut the deaths sharply.

Lipotes, the genus name of the possibly extinct baiji, means what?

Lipotes means 'left behind' in Greek, and the species name vexillifer 'flag bearer'; Qi Qi, the last baiji known in captivity, died in 2002 and a 2006 survey found none in the wild.

As mammals, most dolphins are born with a few of what on the snout, which soon fall out?

Whiskers, a few hairs along each side of the snout, are in most species the only hair a dolphin ever grows; they drop out before or shortly after birth, leaving the skin bare.

Moko, a wild dolphin, made world news in 2008 by doing what for two stranded pygmy sperm whales?

Leading them out to sea was Moko's doing alone, after rescuers at Mahia beach had tried in vain for an hour and a half to stop the two whales from beaching again.

Hector's dolphin has a dorsal fin of what distinctive shape?

Rounded like one of Mickey Mouse's ears, the fin is the easiest way to pick out a Hector's dolphin at sea, since most dolphins carry a fin that sweeps back to a point.

The first commercial dolphinarium, Marine Studios, opened in 1938 in which US state?

Florida's Marine Studios, near St. Augustine, was built so film crews could shoot sea life; it was there that staff found dolphins could be trained to do tricks, and the dolphin show was born.

Keiko, the orca star of Free Willy, was flown to which country for release?

Iceland was where Keiko had been caught as a calf in 1979; set free in 2002, he swam to Norway, where he died the next year.

Old Tom, an orca of Eden, Australia, was famous for helping local boatmen hunt what?

Baleen whales were herded into Twofold Bay by Old Tom and his companions for Eden's whalers to harpoon from open boats; when he died in 1930, the town kept his bones.

Some Shark Bay dolphins catch fish by lifting what to the surface and shaking them out?

Giant snail shells make handy traps: a fish hides inside, and the dolphin carries the shell up and tips the catch into its mouth; the trick spreads among companions rather than from mother to calf.

Tião, a wild bottlenose dolphin, fatally injured a swimmer in 1994 off the coast of which country?

Brazil's São Paulo coast was Tião's home; for months crowds of bathers had grabbed at his fins and tried to hold him for photographs, and dozens were hurt before one swimmer was killed.

The rough-toothed dolphin gets its common name from what feature of its teeth?

Fine ridges along them give each tooth a roughened surface; for all the fierce name, this is one of the few ocean dolphins that settles well into life in an aquarium.

Which Scottish firth holds the world's most northerly resident bottlenose dolphin population?

The Moray Firth's bottlenose dolphins, watched from Chanonry Point near Inverness, form the most northerly resident population of the species; they are larger and fatter than tropical bottlenoses.

The rosy colour of Chinese white dolphins comes not from pigment but from what?

Their pink comes from overdeveloped blood vessels just beneath the skin, which shed heat; adults of this Indo-Pacific humpback dolphin population lose the grey pigment of youth and live up to about 40 years.

Striped dolphins in the eastern Pacific are nicknamed what for fleeing from vessels?

Eastern Pacific striped dolphins earned the nickname 'streakers' for racing away from ships; in the Atlantic and Mediterranean they readily approach boats, and past hunting in the Pacific may explain the difference.

What is the term for dolphins travelling fast in a series of long, low leaps?

Porpoising is fast travel in a series of long, low arcs clear of the water; leaping cuts drag compared with swimming at the surface, so it saves energy at speed.