94 Fun Facts About Otters

Otters are carnivorous mammals belonging to which family, which also includes weasels, badgers, and mink?

Otters are part of the subfamily Lutrinae, which itself is a branch of the larger Mustelidae family. This family encompasses a diverse group of carnivorous mammals known for their long bodies and short legs.

The sea otter is the only living member of which genus?

Enhydra: the sea otter, Enhydra lutris, is the only living species in the genus; the name is Greek for 'in the water', and it is the heaviest member of the weasel family at up to 45 kg.

How do sea otters crack open clams and sea urchins?

Pounding shells open on a rock held on the chest is the trick; they keep a favourite stone in a pouch of skin under the forearm and can hammer 45 times in 15 seconds.

What is a floating group of resting sea otters called?

A raft usually holds 10 to 100 otters, but the largest ever recorded had more than 2,000; they wrap themselves in kelp so the group does not drift apart.

What is the common name for an otter's den or burrow?

A holt sometimes has an underwater entrance; an above-ground resting spot is a couch, while a sett belongs to a badger and a lodge to a beaver.

How does an otter's coat, rather than blubber, keep it warm and dry underwater?

It holds a layer of air against the skin: dense underfur traps the air while long guard hairs keep water out, which is why otters groom for hours to stop the coat getting waterlogged.

Which otter species is known for being the smallest in the world, typically weighing less than 10 pounds?

The Asian small-clawed otter is the smallest otter species, with a maximum weight of 3.5 kg (7.7 lb) and a total body length of 730 to 960 mm (28.6 to 37.6 in).

Unlike most otters, the sea otter is marine: along which ocean's coasts does it live?

The North Pacific: its range runs from northern Japan through the Aleutians and Alaska down to California, and fur-trade hunting had cut the population to perhaps 2,000 animals by the 1911 protection treaty.

What do North American river otters primarily consume in their diet?

Fish, crayfish, and frogs: fish remains turn up in more than 90 percent of river-otter scat samples in some studies, with crayfish the main fallback when fish are scarce.

Which paw feature lets the Aonyx cinerea otter forage by feel in mud and shallow water?

Its claws do not even extend past the pads of its toes, letting it feel out crabs and molluscs almost like hands.

Otters are naturally absent from which two continents?

Australia and Antarctica: otters live on every other continent, from Scottish sea lochs to the Amazon and the coasts of Alaska, in habitats from freshwater rivers to the open sea.

Roughly what share of its body weight does a sea otter eat each day?

About 25 percent: with no blubber and a metabolism two to three times that of a land mammal its size, a sea otter eats roughly a quarter of its body weight every day, mostly clams, urchins and crabs.

Roughly how many hairs per square centimetre does sea otter fur pack?

Up to 150,000 per square centimetre, nearly a million per square inch, and it has to be: sea otters have no blubber, so the fur is their only insulation.

Which two body parts can an otter seal shut to keep water out when it dives?

Ears and nostrils close on cue, and a sea otter can then hold its breath for up to five minutes, though most dives last about one.

What is the term for the distinctive droppings otters leave in prominent spots?

Spraint is the surveyor's term: it smells of anything from freshly mown hay to rotten fish, and British otter surveys rely on finding it on rocks and ledges beside water.

What do otters mainly use their long, stiff whiskers for?

Detecting prey movements in murky water: an otter's whiskers, or vibrissae, pick up the tiny turbulence left by a swimming fish, which is why otters hunt well at night and in silty rivers.

How do sea otters typically rest at the surface?

Floating on their backs: a resting sea otter lies belly-up at the surface with its paws held out of the water to save heat, and it eats, grooms and nurses its pup in the same position.

Approximately how many extant species of otter are recognized worldwide?

13 species are recognised across seven genera, from the Asian small-clawed otter at about a metre and 3 kilograms to the giant otter at 1.7 metres and the sea otter at up to 45 kilograms.

Fishermen in southern Bangladesh breed which otter species to chase fish into their nets, a skill passed from father to son?

Smooth-coated otters work on leashes from the boats; the practice was once widespread across Asia and now survives in the district of Narail.

What made a Santa Cruz sea otter nicknamed 841 famous in summer 2023?

Stealing surfboards: otter 841, a five-year-old female, repeatedly climbed onto surfers' boards off Santa Cruz, California, in July 2023 and chewed them, evading capture teams for weeks.

Which otter carries the scientific name Lutra lutra?

The Eurasian otter is Lutra lutra, named by Linnaeus in 1758; it has the widest range of any otter, from Ireland and Portugal across Asia to Japan and into North Africa.

How many pups does a sea otter usually give birth to at a time?

One: sea otters almost always bear a single pup, and in the roughly two percent of births that produce twins the mother normally raises only one of them.

For about how long does a sea otter pup stay with its mother?

About six months: a sea otter pup rides on its mother's chest and is weaned at six to eight months, by which time it has learned to dive and forage for itself.

A 2020 study linked rock juggling by Asian small-clawed otters to what?

Hunger: the Royal Society Open Science study found captive otters juggled pebbles far more just before feeding time, and the habit did not improve their skill at extracting food from puzzle objects.

The word 'otter' shares a Proto-Indo-European root with which everyday English word?

Water and otter are cousins: Old English 'otor' descends from the root *wódr̥, so the animal's name essentially means 'the water one'.

Sea otters can digest and pass a meal in as little as how long?

About 3 hours: a sea otter's metabolic rate runs two to three times that of a land mammal the same size, and a meal can pass through its gut in as little as three hours.

Seals and sea otters are the only carnivores with how many pairs of lower incisors?

Two pairs: most carnivores carry three, while the sea otter's 32 teeth include flattened, rounded molars for crushing shells rather than slicing meat.

A diet heavy in sea urchins can stain a sea otter's teeth and bones which colour?

Purple: pigments from sea urchins build up over a lifetime of crunching the spiny shells, and the violet tint shows up in skeletons long after death.

What is a newborn sea otter pup unable to do until its adult coat grows?

Dive: the fluffy natal coat traps so much air that the pup bobs on the surface like a cork, and it cannot dive until adult fur replaces it at about 13 weeks.

The 2007 viral video of two sea otters holding paws was filmed at which aquarium?

Vancouver Aquarium: the paler otter, Nyac, had survived the 1989 Exxon Valdez spill; her paw-holding clip with Milo drew millions of YouTube views before she died in 2008.

The 1989 Exxon Valdez spill killed thousands of sea otters in which Alaskan body of water?

Prince William Sound: oiled fur loses its ability to hold air, so otters die of hypothermia, and thousands died after the March 1989 spill, with lingering oil affecting the population into the 2000s.

Orphaned sea otter pups raised by surrogate mothers are released into which estuary?

Elkhorn Slough: Monterey Bay Aquarium aquarists wear black gowns and masks so the pups never bond with humans, and a 2021 study credited the released otters with more than half of the estuary's population growth.

California's sea otters all descend from about 50 found in 1938 near which landmark?

Bixby Creek Bridge: in 1938 a couple testing a telescope from their home spotted the colony below the Big Sur bridge, decades after the species was assumed extinct in California.

Hundreds of sea otters were moved off Amchitka Island in the 1960s ahead of what activity?

Nuclear weapons tests: the Atomic Energy Commission agreed to move otters ahead of the underground blasts of 1969 and 1971, and about 700 were shipped to Alaska, British Columbia, Washington and Oregon between 1965 and 1972.

Overhunting of sea otters near the Commander Islands likely helped wipe out which animal?

Steller's sea cow: fewer otters meant more urchins and less kelp, starving the giant sirenian Georg Steller had described in 1741; the last were killed by 1768.

Survivors of whose 1741 shipwreck wintered by killing nearly 1,000 sea otters for pelts?

Vitus Bering: after the St Peter wrecked on what became Bering Island, Steller and the crew survived the winter of 1741-42 partly on sea otter meat and took some 900 pelts home, sparking the Russian fur rush.

What is the primary predator of sea otters off California?

Great white sharks: they seem to mistake otters for seals and spit them out rather than eat them, yet shark bites became the leading recorded cause of southern sea otter deaths in the 2010s.

Which cat-borne parasite, washed to sea in urban runoff, kills California sea otters?

Toxoplasma gondii: cat faeces flushed through sewers or washed off gardens carry its oocysts into coastal waters, where the parasite causes fatal brain infections in California sea otters.

Sea otters are the only sea mammal that catches fish using what?

Front paws: the sea otter is the only marine mammal that grabs fish with its forepaws rather than its teeth, and the only marine animal known to lift and turn over rocks on the seabed.

The cry of a sea otter pup is usually compared to the call of which bird?

A gull: a pup's cry is usually likened to a seagull's call, while content females coo, males grunt, and frightened adults may whistle, hiss or scream.

In Russian, the Asian sea otter is known by what name?

Kalan: the Russian name for the sea otter; most of the Asian subspecies lives off Kamchatka and the Kuril Islands, the heart of the 18th-century Russian fur trade.

Japan's only resident sea otter population lives off which island?

Hokkaido: a small breeding group settled off the Nemuro peninsula and Kiritappu in eastern Hokkaido in the 2010s, the first resident sea otters in Japan in decades.

By digging for prey, sea otters boost the growth and genetic diversity of which plant?

Eelgrass: a 2021 study in British Columbia found that otters digging for clams disturb eelgrass beds just enough to boost flowering and genetic diversity, and healthier meadows buffer coasts against storm surges.

Which predator is the prime suspect in the crash of Aleutian sea otter numbers to around 6,000 by the year 2000?

Killer whales fit the pattern of the 1990s decline, yet nobody has seen them eating otters in large numbers, so the orca explanation James Estes proposed in 1998 was never directly confirmed.

In which Spanish region do Eurasian otters make use of artificial lakes on golf courses?

Andalusia: a study of golf courses in southern Spain found otters foraging in their artificial lakes, which hold fish and crayfish and stay full through the dry summer.

What chiefly drove the Eurasian otter's decline in the second half of the 20th century?

PCBs and organochlorine pesticides were the culprits; a Europe-wide ban on the worst of them has been in place since 1979.

In 2011 the Environment Agency said otters were back in every county of which country?

England: the Environment Agency's 2011 survey found otters in every English county, Kent the last, after they had vanished from everywhere but the West Country and parts of the north in the 1970s.

How many toes does an otter have on each foot?

Five: each of an otter's four feet carries five webbed toes, and the five-toed print with webbing showing between the toes is the sign surveyors look for in riverside mud.

By 1990 the Eurasian otter was deemed extinct in Liechtenstein and which other country?

It was declared extinct in Switzerland in 1989; elsewhere it is common in Latvia, along Norway's coast, western Iberia and across Britain and Ireland.

The giant otter's genus name Pteronura refers to which distinctive feature?

From the Greek pteron (wing) and oura (tail); the flattened tail can add 70 cm to the animal's length.

The Brazilian name onça-d'água for the giant otter translates as what?

Water jaguar: onça is the Portuguese word for the jaguar, and Brazilians also call the giant otter ariranha, from the Tupi arerãîa, while Spanish speakers use lobo de río, river wolf.

Individual giant otters can be identified from birth by unique pale markings where?

Researchers catalogue the cream-coloured throat patches like fingerprints to track animals across seasons.

When fish are scarce, giant otters will take which formidable prey?

Truly coordinated group hunts seem reserved for prey no single otter could handle, such as juvenile black caiman and small anacondas.

Why, per one researcher, is the giant otter hunted in Suriname only out of desperation?

It tastes horrible: researcher Nicole Duplaix found the giant otter is not a traditional prey species in Suriname and is eaten only in desperation, so 'tolerance is the rule' among fishermen.

In Bororó legend, misusing which plant got people turned into giant otters?

Tobacco: a Bororó myth recorded by Lévi-Strauss tells how people who misused tobacco were transformed into giant otters, an animal the Bororó also associate with fish and fire.

Why do North American river otters often swim to within a few metres of a boat or a person on shore?

Near-sightedness on land is the price of eyes tuned for seeing underwater, so they cannot make out what is in front of them until they are close.

What is the transparent inner eyelid that protects a river otter's eyes underwater called?

Nictitating membrane: this third eyelid sweeps across the eye to shield it underwater; birds, sharks and camels have one too, while in humans only a small pink remnant survives in the corner of the eye.

In 2012 'Sutro Sam' became the first river otter seen in which city since the 1950s?

San Francisco: the otter set up home in late 2012 around the ruins of the Sutro Baths, a seaside swimming complex near Lands End, and was the city's first wild river otter in more than 50 years.

Roughly how much does a newborn sea otter pup weigh?

About 2 kilograms: a sea otter pup is born at 1.4 to 2.3 kilograms, already wrapped in its dense natal coat, and spends its first weeks riding on its mother's chest.

A review of otter attacks on people since 1875 found most happened in which US state?

At least 42 attacks were found, and 36% of anecdotal reports involved a rabid animal.

Sea otter pelts from the maritime fur trade were sold chiefly in which country?

China: Russian, British and American traders shipped sea otter pelts to Canton, where Chinese buyers paid the highest prices for the 'soft gold' that drove the maritime fur trade of the 18th and 19th centuries.

Captive Asian small-clawed otters leave shellfish where so the shells open by themselves?

The heat makes the shells gape, saving the otters the trouble of cracking them with their small teeth.

The Asian small-clawed otter is Asia's most sought-after otter for which illegal trade?

Pets: a 2018 TRAFFIC survey found hundreds of otters advertised online by traders in Indonesia, Malaysia, Thailand and Vietnam in 2016-17, with most seized animals bound for Japan's pet market and otter cafes.

The celebrity 'Bishan family' of urban smooth-coated otters lives in which country?

Singapore: the Bishan family first appeared in Bishan-Ang Mo Kio Park around 2014, and the city's otters climb staircases and ladders to get in and out of concrete canals and den in gaps under buildings.

Smooth-coated otters in Malaysia were seen hunting in what formation to panic fish?

A V-shaped line: the biggest otters take the middle of the line while the others flank them, and fish leaping ahead of the advancing wave are caught and swallowed head-first on the bank.

In 2013 six young smooth-coated otters were found in a bag at which city's airport?

It was the first case of the species thought to be headed for the illegal pet trade.

Lutra sumatrana, Asia's rarest otter, is named for short dark fur on which body part?

Its nose: the hairy-nosed otter's rhinarium is covered in short dark fur rather than bare skin, unique among otters; it was feared extinct in the late 1990s before small populations were rediscovered in Thailand, Cambodia, Vietnam and Sumatra.

When is the giant otter mainly active?

During the day: the giant otter is diurnal, hunting fish by sight in clear water and spending the night in a communal den, which makes it far easier to observe than its nocturnal cousins.

South Africa's Otter Trail hiking route runs through which national park?

Tsitsikamma: the five-day Otter Trail follows the coast of the Tsitsikamma section of the Garden Route National Park and takes its name from the Cape clawless otters that live along it.

In Gabon, otters are rarely hunted because of a myth that they can do what when speared?

Otter bushmeat is common in Congo and Cameroon, where the fur is also used to make drums.

Which species, the family's greatest generalist, has settled in sewage treatment plants?

It also turns up in rice paddies, sugar-cane plantations and glacial Andean lakes up to 3,000 metres.

Which introduced mustelid competes with the southern river otter in Patagonia?

American mink: escaped from Patagonian fur farms from the 1930s, the mink competes for food and shelter with the southern river otter, known locally as the huillin, which survives in scattered populations in Chile and Argentina.

Roughly how deep can a sea otter dive at most?

About 100 metres: the deepest recorded sea otter dive reached 97 metres, though most feeding dives are far shallower and last one or two minutes.

A 2026 Chilean study found which human-linked cause topped deaths of Lontra felina?

Fisheries bycatch came second; microplastics have also turned up in the species' scat.

In what year did Japan's government officially declare the Japanese otter extinct?

2012: Japan's Ministry of the Environment declared the Japanese otter extinct in August 2012; the last official sighting was in 1979 at a river mouth in Kochi Prefecture, and it was once found even around Tokyo.

The Japanese otter was once used as a medicine against which disease?

A 40-day course cost roughly $300; a 1929 'Hunters Association' drive for pelts helped push the species to extinction.

In Ishikawa and Kochi folklore, the otter (kawauso) is seen as a type of which yōkai?

Kappa: in Ishikawa and Kochi folklore the otter is a kind of kappa, and the Muromachi-period dictionary Kagakushu even claims that an otter that grows old becomes a kappa.

In Korean folk belief, people who see an otter attract what for the rest of their lives?

The Korean word for otter is soodal; in Zoroastrian tradition the animal is clean and taboo to kill.

Which religion holds the otter to be a clean animal of Ahura Mazda that is taboo to kill?

In Norse myth, by contrast, the dwarf Ótr is killed in otter form, setting the Volsunga saga in motion.

Which otter bone did British hunters prize as a trophy to wear as a tie-pin?

Aleut hunters, by contrast, ground up sea otter bacula as a medicine for fever.

Otter hunting with hounds ended in England and Wales in which year?

1978: otters became legally protected in England and Wales from January 1978, ending hunting with hounds; nine registered otterhound packs were running the year before, and some switched to mink or coypu.

Otters belong to which suborder of the order Carnivora?

Caniformia: the 'dog-like' suborder of Carnivora holds the weasel family along with dogs, bears, raccoons and seals, as opposed to Feliformia, the cat-like branch with cats, hyenas and mongooses.

Which 1653 angling classic describes training otter pups to drive fish into nets?

Izaak Walton's pups were muzzled so they could not eat the catch and kept on lines to their master.

Otter fishing in southern Bangladesh is usually carried out at what time?

At night: the fishermen work with their otters between about 9 PM and 5 AM, and a single boat brings in 4 to 12 kg of crabs, fish and shrimp a night; a 2011 count found 176 otters at work.

Who wrote the 1927 novel Tarka the Otter?

Henry Williamson: Tarka the Otter took him four years of research on Devon's rivers, won the 1928 Hawthornden Prize and has remained in print ever since.

Tarka the Otter is set in the 'Country of the Two Rivers' — which Devon rivers?

Taw and Torridge: Williamson set the book around the two North Devon rivers, and the Tarka Line railway to Barnstaple and the Tarka Trail footpath are both named after it.

Which American nature writer said Tarka the Otter had 'deeply influenced' her?

Rachel Carson: the author of Silent Spring named Tarka and Williamson's Salar the Salmon as two of the three books she would take to a desert island.

Mijbil, the otter star of Ring of Bright Water, came from the marshes of which country?

Iraq: Maxwell brought Mij home from the Tigris marshes in 1956 after travelling there with Wilfred Thesiger; London Zoo found he belonged to an unknown subspecies, named Lutrogale perspicillata maxwelli after his owner.

Which of Gavin Maxwell's otters died in the 1968 fire that destroyed his Sandaig home?

Edal: she died in the January 1968 fire at Sandaig, the Camusfearna of the books; Maxwell lost almost all his possessions and moved with Teko to a lighthouse keeper's cottage on Eilean Ban, beneath what became the Skye Bridge.

Emmet Otter's Jug-Band Christmas was inspired by which O. Henry story?

Jim Henson's 1977 special, with songs by Paul Williams, first aired on CBC before reaching HBO and ABC.

In The Wind in the Willows, what is the name of Otter's young son?

Portly: Rat and Mole find Otter's lost son asleep at the feet of the god Pan in 'The Piper at the Gates of Dawn', a chapter often cut from adaptations.

Enhydriodon omoensis, an extinct lion-sized otter, was unearthed in which country?

Ethiopia: the fossils come from the Lower Omo Valley and were described in 2022; estimated at over 200 kg, it may be the largest mustelid that ever lived, and isotope evidence suggests it hunted on land.

Mionictis, the first otter genus, evolved in the Early Miocene from which animals?

The split happened as some of those ancestors adapted to a semi-aquatic life; otters remain close kin of the weasel subfamily.

An otter pup can leave the den after one month; after how long can it swim?

Two months: a pup can leave the holt after about a month and swim at around two months, then stays with its family for about a year; gestation across otter species runs roughly 60 to 86 days.