85 Fun Facts About Dolphin

Which competitive swimming stroke is powered by the 'dolphin kick', with both legs beating up and down together?

Butterfly swimmers whip both legs together in a wave modelled on a dolphin's tail; the kick is so effective underwater that racing rules make swimmers surface within 15 metres of each start and turn.

For what primary purposes do dolphins use echolocation?

Navigation and hunting both depend on it: a dolphin sends out rapid clicks and reads the echoes, so it can find its way and track prey in dark or murky water where eyes are little use.

A dolphin's blowhole is the evolutionary counterpart of which human feature?

The nostrils of dolphins' land-dwelling ancestors moved back along the skull over millions of years to become the blowhole, which lets a dolphin breathe while barely breaking the surface.

In a landmark mirror test, what did bottlenose dolphins do after researchers marked their bodies with dye?

Twisted to inspect themselves: both dolphins swam to the mirror and turned the marked part of the body toward it, a sign of self-recognition shown before only by humans and great apes.

Which lifelong mark of birth, familiar from the human body, does every dolphin carry on its underside?

A belly button marks the spot where the umbilical cord snapped at birth; like every mammal nourished through a placenta, a dolphin keeps the scar for life.

In the US Navy, sailors who earn their 'dolphins' have qualified to serve aboard what?

Submarines: the badge shows a submarine's bow flanked by two dolphins, and a sailor wins it only after about a year spent learning every system on the boat.

How do dolphins usually eat a fish?

Swallow it whole, and head first, so the fish's spines lie flat instead of catching in the throat; the teeth are there only to grip slippery prey.

A dolphin's smooth skin is most often said to feel like which material?

Rubber is the usual comparison: the skin is smooth and free of sweat glands, and its sleekness helps a dolphin slip through the water with less drag.

How does a dolphin manage to sleep without drowning?

Half its brain stays awake while the other half sleeps, along with the opposite eye; the alert side watches for danger and tells the dolphin when to surface for air.

Dolphins killed for meat at Taiji, Japan are caught by what method?

Drive hunting means boats herd dolphins into a bay and shut the way back to sea with nets; Taiji is the only town in Japan still doing it on a large scale, and the Faroe and Solomon Islands run drives too.

Dolphins, whales and porpoises together make up which group?

Cetacea comes from the Greek ketos, a whale or sea monster; every member is a mammal whose ancestors walked on land before returning to the water some 50 million years ago.

What name is given to the low leaps that travelling dolphins make to save energy?

Porpoising, a run of low leaps made at speed, uses less energy than swimming fast at the surface because air drags far less than water; a dolphin moving quickly enough simply breaks free with each stroke.

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

Tail first is the usual way, though head-first births are also seen; the calf arrives underwater, and a second dolphin, nicknamed an 'auntie', sometimes stays close to mother and newborn.

Which land animal is the closest living relative of dolphins?

The hippopotamus is dolphins' closest living relative, though it looks more like a pig: DNA studies group hippos and whales together as Whippomorpha, which split from a common ancestor over 50 million years ago.

The 'wholphin' at Sea Life Park is a cross between a bottlenose dolphin and which species?

Kekaimalu, born at Sea Life Park in 1985, had a false killer whale father and a bottlenose mother; she later produced calves of her own, and wild wholphins have also been reported.

Which cooperative hunting method involves dolphins driving fish onto the shore to catch them?

Strand feeding is seen in bottlenose dolphins of South Carolina and Georgia: they drive fish onto mudbanks, briefly beach themselves to grab them, then slide back into the water.

In Shark Bay, Australia, what do bottlenose dolphins wear on their snouts while rooting through the seabed?

The habit is passed mostly from mothers to daughters, one of the clearest cases of culture and tool use outside primates.

Spinner dolphins do most of their hunting when?

After dark, the small fish and squid they eat rise from the depths toward the surface, so spinner dolphins head offshore at night to meet them and return to shallow bays to rest.

Which dolphin sound is used mainly for individual identification and long-distance communication?

A signature whistle works like a name: it forms in the first year of life and stays the same for life, and dolphins have recognised the whistles of old companions after 20 years apart.

Which sense is largely absent in dolphins, unlike most land animals?

Dolphins have almost no sense of smell: their brains lack olfactory lobes and nerves entirely, so they rely on hearing and echolocation instead.

What shape are the teeth of most dolphin species?

Conical and pointed teeth interlock to hold slippery prey; porpoises, often mistaken for dolphins, have spade-shaped teeth instead.

How often do dolphins typically renew their outer skin layer?

Dolphins have a remarkably rapid skin renewal process, shedding and replacing their outer skin layer approximately every 2 to 3 hours. This helps maintain their smooth surface for efficient swimming and protects against microorganisms.

The orca and pilot whales belong to a group of dolphins known by which collective nickname?

'Blackfish' is the old nickname for the orca, the pilot whales and a few dark-bodied relatives; pilot whales often beach themselves in whole groups, perhaps because their social bonds are so strong.

Which of these is the smallest dolphin species?

Hector's dolphin is the smallest of these, with adults only about 1.2 to 1.6 metres long; it keeps to shallow coastal water, which puts it in the path of fishing nets, its main threat.

What is a major natural predator of dolphins?

The great white shark is one of a few large sharks, with bull, tiger and dusky sharks, that prey on dolphins, mostly the young; healed shark-bite scars are common on wild bottlenose dolphins.

What type of social structure do many dolphin species exhibit?

Groups merge and split several times a day, and where food is plentiful they can swell into a superpod of over 1,000 animals.

In one Greek myth, which god set a dolphin among the stars for persuading Amphitrite to marry him?

Poseidon sent a dolphin after the sea nymph Amphitrite, who had fled his advances; when it coaxed her back to marry him, he placed its image in the sky as the constellation Delphinus.

What is the primary purpose of a dolphin's pectoral fins?

Steering and braking are the flippers' job, with the tail supplying the thrust; inside each flipper are the same forelimb bones found in land mammals, shortened into a paddle.

What is the common name for the dolphin family Delphinidae?

Oceanic dolphins, the family Delphinidae, take in most dolphin species, from the orca down; the river dolphins belong to separate families and do not form one natural group.

The baiji, declared functionally extinct after a 2006 survey found none, lived in which river?

Yangtze fishermen regarded the baiji, nicknamed the 'Goddess of the Yangtze', as a protector; as the river grew crowded and polluted its numbers collapsed, and a six-week search in 2006 found none.

A dolphin's dark back and pale belly make up which kind of camouflage?

Countershading works in both directions: seen from above, the dark back merges with the deep water, and from below the pale underside melts into the bright surface; sharks wear the same pattern.

A dolphin's echolocation works on the same principle as which sound-based technology used by ships?

Sonar sends out pulses of sound and times the echoes, just as a dolphin does with its clicks; the US Navy began keeping dolphins in the 1960s partly to study their natural version.

Which physical adaptation allows dolphins to maintain their body temperature in cold ocean waters?

A thick layer of blubber makes up about a fifth of a bottlenose dolphin's weight and holds heat so well that the animal sheds any excess through its thin flippers, flukes and dorsal fin.

How well does a typical dolphin see?

Good both underwater and in air: the eye is built for seeing in water, and when a dolphin surfaces its lens and cornea correct the blur that the switch to air would otherwise cause.

Dolphins breathe through a single blowhole, but which whales have two side by side?

Baleen whales such as humpbacks and right whales have paired blowholes, which is why a right whale's spout rises in a V; dolphins and all other toothed whales have just one.

In Shark Bay, male bottlenose dolphins form small, stable alliances mainly in order to do what?

Herd and guard females: two or three allied males flank a fertile female for weeks at a time, and whole alliances fight rival alliances for control of her.

What are dolphins doing when they 'rake'?

Scratching a rival with their teeth leaves long, thin parallel scars known as rake marks; Risso's dolphins collect so many that old animals look almost white.

In one Greek myth, the dolphin that rescued the singer Arion was set among the stars beside which instrument of his?

A lyre: Arion sang one last song to its music before leaping from a ship whose crew meant to rob and kill him, and his rescuer and instrument became the constellations Delphinus and Lyra.

How do scientists primarily determine the age of a dolphin?

By counting growth layers in their teeth, much as tree rings are counted; a tooth taken in 1984 from Nicklo, a wild Florida dolphin, showed she was 67 when last seen in 2017.

Newborn dolphins have what on their snouts, which drops off soon after birth?

Whiskers line each side of a newborn's snout in a single row and soon fall out; they may help the calf find its mother's teats, and they are the only hair a dolphin ever grows.

A bottlenose dolphin's echolocation clicks are pitched mostly in which range?

Ultrasonic (above human hearing): the clicks peak at up to 150 kHz, far beyond the roughly 20 kHz ceiling of our ears, while the calls dolphins use socially carry most of their energy lower down.

Instead of an outer ear, dolphins mainly receive sound through what part of the body?

The throat and jaw take in sound, which passes through a fat-filled channel to the inner ear; air-filled sinuses isolate the ear from the skull, so the dolphin can tell where a noise comes from.

The species Delphinus delphis goes by which everyday name?

Common dolphin fits: it is among the most abundant dolphins on Earth, yet the bottlenose, a staple of aquariums and television, is the one most people picture.

Dolphins get most of their fresh water from what?

The fish they eat supply most of a dolphin's fresh water, and breaking down food releases more inside the body; drinking seawater is not something dolphins are known to do routinely.

What is the scientific term for a dolphin's beak-like snout?

The rostrum is the elongated jaw that forms a dolphin's beak; bottlenose dolphins take their name from its short, stubby shape, while common dolphins carry a long slender one.

Ecco the Dolphin, a 1992 video game about a dolphin seeking his lost pod, was published by which company?

Sega released Ecco the Dolphin for its Mega Drive, sold as the Genesis in North America; it wanted a series of its own to set against Nintendo's, and Ecco went on to several sequels.

What is the muscular tail stock between a dolphin's body and its flukes called?

The peduncle is the engine room: its muscles sweep the flukes up and down, the stroke that drives a dolphin forward and launches its leaps.

What is an adult male dolphin called?

A bull is an adult male dolphin and a cow a female; bulls scar one another so often in fights that the 'male' star of TV's Flipper was played by smoother-skinned females.

Which fish, popular on restaurant menus, is confusingly known as the dolphinfish?

Mahi-mahi, a Hawaiian name meaning 'very strong', is the dolphinfish; the fish was long called simply 'dolphin', and the longer name was coined to avoid confusion with the mammal.

Which title was borne by the heir apparent to the French throne?

The Dauphin owed his title to the dolphin on the arms of the lords of Viennois, whose Alpine province became known as the Dauphiné and passed to the French royal house in 1349.

Which Greek historian tells how a dolphin carried the poet Arion to shore after sailors forced him overboard?

Herodotus tells it early in his Histories: robbed at sea, Arion sang a last song in full costume, leapt overboard and was carried by a dolphin to Cape Taenarum, reaching Corinth before the thieves.

Which endangered species is India's national aquatic animal?

The Ganges river dolphin is all but blind: its tiny eyes lack a lens and are little use in murky water, and it often swims on its side, trailing a flipper to probe the riverbed for food.

In a Homeric hymn, which god wreathed a pirate ship in vines before the pirates leapt overboard and became dolphins?

Dionysus, god of wine, had been seized by pirates who took him for a king's son; before they jumped, he also turned into a roaring lion on deck.

Dolphin meat sold in Japan has repeatedly tested high in which toxic metal?

Mercury builds up in long-lived predators near the top of the food chain; Japan's health ministry has advised since 2003 that pregnant women and children limit how much dolphin they eat.

Wild dolphin Billie picked up which show trick during a stay in an Adelaide marine park?

Tail-walking was never taught to Billie: during a few weeks beside captive dolphins in the 1980s she watched them do it, and back in the Port River other wild dolphins copied her.

Two small bones buried deep in a dolphin's body are the last remnants of which feature of its ancestors?

Hind legs dwindled as early whales took to the sea, leaving two rod-shaped pelvic bones; in 2006 a bottlenose caught off Japan had an extra pair of fins near its tail, a rare throwback.

On the 1960s TV series Flipper, the dolphin's 'voice' was really the call of which bird?

A kookaburra's laughing call, sped up, became Flipper's 'voice'; dolphins have no vocal cords and make their real sounds with air sacs inside the head rather than a voice box.

The 1960s TV series Flipper was filmed with help from a Seaquarium in which Florida city?

Miami Seaquarium supplied the five dolphins who shared the title role; their trainer, Ric O'Barry, later turned against captivity and led the campaign shown in the documentary The Cove.

Fungie, a lone wild dolphin who greeted boats in Dingle harbour for 37 years, lived in which country?

Ireland's Dingle, in County Kerry, was Fungie's home from 1983 until he vanished in 2020; he lived so long that rumour claimed a lookalike had been slipped in to protect the tourist trade.

Which young actor starred opposite Paul Hogan when Flipper was remade for cinemas in 1996?

Elijah Wood played the teenager sent to spend a summer with his uncle in Florida; real dolphins proved awkward on set, so animatronic doubles did much of Flipper's acting.

Pelorus Jack was adopted in 1989 as the emblem of which New Zealand service?

Interislander ferries cross Cook Strait near the waters where Pelorus Jack, a Risso's dolphin, met steamers from 1888 to 1912; sailors came to believe no ship he escorted would be wrecked.

Opo, the dolphin who played with children at Opononi, died in 1956 one day after what?

Legal protection became law on 8 March 1956, and Opo was found dead the next day, wedged among rocks; the grieving townspeople buried her beside Opononi's war memorial hall.

Winter, the dolphin with a prosthetic tail, lived at an aquarium in which Florida city?

Winter lived at the Clearwater Marine Aquarium from 2005 until her death in 2021; the gel sleeve designed for her tail was later adapted to ease prosthetic limbs for human amputees.

Winter, the dolphin whose prosthetic tail inspired the film Dolphin Tale, lost her tail in 2005 after becoming tangled in what?

The rope cut off the blood supply: a crab trap line wrapped Winter's tail, and without flukes she swam side to side like a fish, which threatened her spine.

Adult Amazon river dolphins, or botos, are famous for turning what colour, most strongly in battle-scarred males?

Pink deepens with age and wear: the colour is thought to come from repeated scraping and scarring of the skin, so the most battle-scarred males are the rosiest, hence 'pink river dolphin'.

The Amazon river dolphin's unusually flexible neck helps it hunt among obstacles in which seasonal habitat?

Flooded forest covers thousands of square miles of the Amazon basin each wet season, and the boto swims in among the trunks; unfused neck vertebrae let it turn its head 90 degrees to weave between them.

In Amazon folklore, the river dolphin is an 'encantado' that appears at night as what?

A handsome young man is the boto's night-time disguise in the tale: he seduces village girls and slips back into the river by morning, and legend adds that meeting a boto's eye brings lifelong nightmares.

Irrawaddy dolphins are popular in aquarium shows partly for which unusual habit?

Spitting water may be a hunting aid: Irrawaddy dolphins squirt streams from the mouth, possibly to herd fish, a habit that helped make them favourites in Asian dolphinariums.

The critically endangered Maui dolphin is found only off which coast?

Maui dolphins live only off the west coast of New Zealand's North Island; post-mortems found toxoplasmosis, a parasite spread by cats, among the confirmed causes of death.

Philibert Commerson, sailing on Bougainville's voyage from France to the Pacific, first described his namesake dolphin in 1767 in which strait?

Strait of Magellan sightings in 1767 gave Commerson his dolphin; his assistant on the voyage, Jeanne Baret, sailed disguised as a man and is recognised as the first woman to circle the globe.

The hourglass dolphin was accepted as a species in 1824 on the strength of what alone?

Quoy and Gaimard named the hourglass dolphin in 1824 from a drawing made at sea, with no specimen in hand; whalers called the Antarctic dolphin a 'sea skunk', and cruciger means cross-bearer.

Risso's dolphins usually have just two to seven pairs of teeth, all located where?

Risso's dolphins carry their two to seven pairs of peg-like teeth only in the lower jaw, suited to a diet almost entirely of squid; older animals are so scarred they look nearly white.

A spinner dolphin's mid-air spins may help shake off which hitchhiking fish that cling to its skin?

Remoras hold on with a sucker on top of the head; a spinner dolphin, which can whirl up to seven times in one leap, may be shaking them loose, though experts think the spins mainly send signals.

Purse-seine fishing for which fish killed tens of thousands of spinner dolphins?

Tuna purse seines in the eastern tropical Pacific killed huge numbers of spinner and spotted dolphins, which school above yellowfin tuna; the outcry produced the 'dolphin safe' label in 1990.

The US Navy's Marine Mammal Program trains its dolphins in the bay of which city?

The Navy Marine Mammal Program is based at Point Loma on San Diego Bay; its dolphins sweep for sea mines and mark intruding divers, and the Navy says they are never trained to attack.

In 1965, Navy dolphin Tuffy ferried tools to divers in which undersea habitat?

SEALAB II sat about 205 feet down off La Jolla in 1965; Tuffy carried tools and mail between the surface and the habitat and was trained to guide lost divers back to safety.

In the 2003 Iraq War, US Navy dolphins helped find more than 100 mines at which port?

Umm Qasr is Iraq's deep-water port, and its approaches had to be cleared before ships could dock; the Navy credits its dolphins with helping to detect more than 100 mines and underwater booby traps there.

A 2022 study filmed which dolphins rubbing against Red Sea corals, apparently to treat their skin?

Indo-Pacific bottlenose dolphins were seen rubbing against particular corals, which turned out to release compounds with antibacterial activity, so the habit may be a form of self-medication.

In the constellation Delphinus, the star names Sualocin and Rotanev spell what when read backwards?

An astronomer's name: reversed they give Nicolaus Venator, the Latin form of Niccolò Cacciatore, assistant at Palermo Observatory, whose 1814 star catalogue slipped the names in unexplained.

The Cove, a 2009 documentary on the Taiji dolphin hunt, won which honour in 2010?

The Cove won the Academy Award for Best Documentary Feature at the March 2010 ceremony; parts were shot in secret with high-definition cameras disguised as rocks.

Dolphin-communication researcher John C. Lilly is also credited with inventing what?

Lilly built the first isolation tank in 1954 while at the NIH; he later flooded part of a Virgin Islands lab so a human and a dolphin could live together, and his work inspired Altered States.

The word 'dolphin' traces back to a Greek word related to which body part?

Womb in Greek is delphys, close kin to delphis, 'dolphin', so the name is often read as 'fish with a womb'; Old English had its own word, mereswine, literally 'sea pig'.

How does a bottlenose dolphin's brain weight compare with a human's?

Bigger than ours, if only just: at 1,500–1,700 grams a bottlenose brain is slightly heavier than a human's 1,300–1,400 grams and about four times a chimpanzee's 400.

In Laguna, Brazil, wild dolphins have teamed up with local people for generations to do what?

Catch fish: the dolphins push shoals of mullet toward fishers standing in the shallows and cue them when to cast their nets; the partnership pays both sides, as the dolphins snap up fish that escape.

Which actor played the prosthetics expert who builds Winter's new tail in the 2011 film Dolphin Tale?

Morgan Freeman's Dr McCarthy stands in for the real prosthetists, who took about a year and a half to perfect the tail; Winter, the dolphin herself, played her own part.