50 Fun Facts About Hard Otter

Potamotherium valetoni, the earliest known otter species, lived on which continent?

The African clawless otter, by contrast, does not appear in the fossil record until the Pleistocene.

Besides lacking a long muscular tail, the sea otter is unique among mustelids in lacking what?

It is also the only mustelid able to spend its whole life without leaving the water.

Roughly what share of its body weight must a Eurasian otter eat every day to stay warm?

Sea otters need even more, 20 to 25 percent or higher. In water of 10 °C an otter must catch about 100 grams of fish an hour just to survive.

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

Otters remain part of the family Mustelidae alongside badgers, weasels, martens and minks.

Between 1958 and 1963 the 11 otter hunts of England and Wales killed how many otters between them?

Hunters notched their poles after each kill and prized the animal's baculum, or penis bone, as a tie-pin.

A 2011 IUCN review found otter attacks on humans from 1875 to 2010 were most common in which US state?

Most involved the North American river otter, and rabies featured in about a third of anecdotal reports. Eighty percent of bite victims never seek treatment.

As late as 1982, some scientists thought the sea otter was closer to which animals than to other mustelids?

Genetics settled it: the sea otter shares an ancestor about five million years ago with the Eurasian, African clawless and Asian small-clawed otters.

Under what scientific name did Linnaeus originally describe the sea otter in 1758?

The name went through many changes before Enhydra lutris, Greek for 'in the water' plus Latin for otter, was accepted in 1922. It was once called the sea beaver.

Which naturalist, shipwrecked with Bering in 1741, first described the sea otter scientifically?

The survivors spent the winter on Bering Island hunting the animals and gambling with the pelts, kicking off 170 years of commercial slaughter.

What nickname did sea otter pelts earn after Cook's crew sold them for high prices in China in the 1770s?

Cook had bought the furs from First Nations people on Vancouver Island in 1778. Word of the profits drew traders from across the Atlantic world.

By the end of the fur trade in 1911, the world sea otter population had fallen to roughly what?

Numbers had once been estimated at 150,000 to 300,000. The species now occupies about two-thirds of its former range but remains classed as endangered.

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

The historic California population had been about 16,000. That 1938 genetic bottleneck left lasting inbreeding and harmful mutations in the population.

Sea otters were moved off Amchitka Island in the late 1960s because the US government planned to use it for what?

The Atomic Energy Commission agreed to relocate hundreds of animals before a 1968 test. Some 700 sea otters were transplanted along the coast in the 1960s and 70s.

How many sea otters were moved from Alaska to Vancouver Island between 1969 and 1972?

The island's own remnant population had died out by 1929 despite the 1911 treaty. The transplants grew to more than 5,600 animals by 2013.

What did most of the 140 sea otters moved to San Nicolas Island in the late 1980s do?

Another twenty swam 119 km to San Miguel Island and had to be recaptured. The plan for an oil-spill insurance colony left just 30 otters there by 2005.

At least how many sea otters were killed by the 1989 Exxon Valdez spill in Prince William Sound?

Oiled fur loses its trapped air layer and the animals die of hypothermia. Lingering oil was still affecting the population in 2006.

Where does a sea otter stash food and its favourite rock while diving?

It prefers the left pouch. At the surface it floats on its back and uses its lower incisors to dig meat out of shellfish.

Why are a sea otter's teeth and bones sometimes stained purple?

Its 32 teeth are flattened for crushing, and seals and sea otters are the only carnivores with two pairs of lower incisors instead of three.

An abalone grips its rock with a force equal to how many times its own body weight?

Otters have been timed at 45 blows in 15 seconds with a large stone. Sea otters are the only marine mammals that catch fish with their forepaws rather than their teeth.

How does a sea otter's metabolic rate compare with that of a similarly sized land mammal?

It eats 25 to 38 percent of its body weight daily and digests food in as little as three hours. Unusually for a marine mammal it also drinks seawater.

Why can a newborn sea otter pup float like a cork but not dive?

Mothers lick and fluff a newborn for hours. Twins occur in about 2 percent of births, but usually only one pup survives.

Which institution first raised sea otters from conception to adulthood, with the birth of Tichuk in 1979?

The same aquarium housed the oldest recorded female, Etika, who lived to 28, and the oldest male, Adaa. Sea otters are kept in more than 40 zoos and aquariums.

The famous 2007 YouTube video of two sea otters holding paws was filmed where?

It drew 1.5 million viewers in two weeks and was YouTube's most popular animal video at the time. Rescued pups Joey and Tofino from the same city later went viral too.

The nominate sea otter subspecies ranges across the Commander archipelago and which other island chain?

It is the largest of the three subspecies, with a wider skull. E. l. kenyoni ranges from the Aleutians to Oregon and E. l. nereis lives off California.

Streamer DougDoug's birthday streams for which Monterey Bay Aquarium sea otter have raised over $1 million?

The charity streams began in 2019. Rosa was one of the aquarium's surrogate mothers, raising stranded pups for release into the wild.

In Brazil the giant otter is called ariranha or onça-d'água, meaning what?

Spanish speakers use lobo de río, river wolf, and perro de agua, water dog. All four names are still used across South America.

How can individual giant otters be identified from birth?

Researcher Nicole Duplaix's 1970s fieldwork was the first serious science on the species. Its fur is the shortest of any otter yet dense enough that water never reaches the skin.

Unusually for a mustelid, the giant otter is what?

Family groups of three to eight are built around a dominant breeding pair and clear large 'campsites' near feeding areas. Poaching peaked in the 1950s and 60s.

In which year was the giant otter listed as endangered, with wild estimates under 5,000?

The Guianas are among its last strongholds. Its wing-like tail and webbed feet make it a fast swimmer in the Amazon and Pantanal.

Which pollutants were mainly blamed for the Eurasian otter's collapse in the late 20th century?

Recovery has been striking: UK sites with otters rose 55 percent between 1994 and 2002.

In August 2011, which body announced that otters had returned to every county in England?

They had previously vanished from everywhere but the West Country and parts of the north. The species is thought to be extinct in Switzerland and Liechtenstein.

Eurasian otter bones show osteosclerosis. What does that do for the animal?

The species is strongly territorial; a river territory averages about 18 km but ranges from 1 to 40 km depending on food.

Since 1976, thousands of North American river otters have been reintroduced across how many US states?

Kentucky's 1990s reintroduction succeeded so well that a trapping season was opened in 2006. The species remains rare in Arizona, Kansas and Ohio.

Which Canadian province is the only one without a viable, harvestable river otter population?

Twenty-nine US states also sustain annual harvests. New World river otters are now placed in the genus Lontra rather than Lutra.

How many Asian small-clawed otters did 280 Southeast Asian traders offer online in 2016-17?

It is the species most sought after by Asia's illegal pet trade. Of 49 animals confiscated from traffickers between 2015 and 2018, 35 were bound for Japan.

Singapore's famous urban otters include an unusual population of at least 60 animals that are what?

Smooth-coated males bred with small-clawed females and the offspring bred back into the smooth-coated population. The city's otters use staircases to climb out of concrete canals.

A smooth-coated otter subspecies from the Tigris marshes was named maxwelli after whom?

He brought the otter Mijbil back from Iraq and raised it at Camusfeàrna, the west Highland house he wrote about in Ring of Bright Water.

Which otter is described as the rarest in Asia, locally extinct in India, Singapore and Myanmar?

Only a few scattered populations survive from southern Thailand to Sumatra and Borneo, threatened by wetland loss, hunting and fishing bycatch.

The scientific name of the South American species Lontra felina translates as what?

Locals call it gato marino, the sea cat. It lives only in saltwater and oddly prefers rocky shores battered by strong swells.

The spotted-necked otter is common in which great African lake?

Hydrictis maculicollis lives in lakes and large rivers south of 10°N and never ventures into salt water.

The African clawless otter is closely related to which extinct giant otter of Sardinia?

The genus name Aonyx means 'without claw'. The species is the second-largest freshwater otter and first appears in the fossil record in the Pleistocene.

How many known isolated populations of the southern river otter, or huillín, survive?

A century of pelt hunting caused the crash. Argentina outlawed hunting from 1960, but it remains legal in Chile.

The Japanese otter, declared extinct in 2012, remains the official animal symbol of which prefecture?

The last official sighting was in Kōchi Prefecture in 1979. It was once seen even in Tokyo before the population crashed in the 1930s.

A sea otter can hold its breath for up to five minutes, but its foraging dives typically last how long?

It is the only marine animal able to lift and turn over rocks, which it does with its front paws while hunting on the sea floor.

Henry Williamson's Tarka the Otter, set on Devon's rivers, won which literary award in 1927?

Williamson said the name means 'wandering as water'. The book influenced Ted Hughes and Rachel Carson and has never been out of print.

What unusual mark does volume three of the Ring of Bright Water manuscript carry?

He wrote the 1960 bestseller in longhand with a fountain pen, much of it outdoors beside a waterfall at Sandaig. It sold more than two million copies.

How many distinct vocalisations did researcher Nicole Duplaix identify in the giant otter?

Giant otters may be the most vocal of all otters; 'hah' barks and explosive snorts signal interest or danger.

A 1998 phylogenetic study found the giant otter's lineage split from other otters roughly how long ago?

Koepfli and Wayne found the giant otter has the highest divergence within the otter subfamily and may be its basal branch.

Up to how many strands of hair per square centimetre does a sea otter's fur pack, the densest of any animal?

With no blubber, the sea otter relies on fur so dense that a trapped air layer keeps cold water off its skin entirely.

Sea otters and which other animals are the only carnivores with two pairs of lower incisors instead of three?

An adult sea otter's 32 teeth are flattened for crushing shellfish; its dental formula is 3.1.3.1 over 2.1.3.2.