52 Fun Facts About Beaver

Which animal beats the beaver as the world's largest living rodent?

The capybara of South America can weigh twice as much as a typical beaver; like a hippo, it carries its eyes, ears and nostrils high on its head, so it can hide from predators almost wholly under water.

What gives a beaver's front teeth their distinctive orange colour?

Iron compounds in the enamel turn the teeth orange and make them tougher than most rodents', so a beaver can bite through hardwoods such as oak and maple without cracking them.

When a beaver slaps its tail hard on the water, what is it doing?

Warning other beavers of danger is the point: at an adult's slap the others dive for deep water, but a youngster's slap is often ignored, because juveniles have not yet learned when to use it.

What kind of eater is a beaver?

Beavers are herbivores: bark, twigs, aquatic plants and sedges are the menu; the fish are just neighbours in the pond.

What are baby beavers called?

Baby beavers are kits; they can eat solid food within two weeks of birth but cannot gather it, so both parents carry greenery home to them.

Which Canadian coin has carried a beaver on its reverse since 1937?

The nickel has shown the artist Kruger Gray's beaver since 1937, with one wartime break: from 1943 to 1945 a Victory design took its place, its rim spelling out in Morse code 'We win when we work willingly'.

Which US state is nicknamed the Beaver State?

Oregon owes the nickname to the fur trade: trappers after beaver pelts were among the first outsiders to arrive, and the animal later became the state's official symbol and Oregon State University's mascot.

Beavers' dome-shaped homes of sticks and mud are known as what?

Beavers build lodges, often in the middle of the pond; the only way in is through underwater entrances, which keeps land predators out.

The beaver genus name Castor comes from a word in which ancient language?

Greek kastor meant beaver; when Latin borrowed the word it pushed aside Latin's own name for the animal, fiber, which survives today in the Eurasian species' scientific name, Castor fiber.

At most, roughly how long can a beaver hold its breath underwater?

15 minutes is the limit, though most dives last only five or six; oversized lungs let a beaver cover more than half a mile under water on a single breath.

A beaver's tail does the steering, so what mainly drives it forward when it swims?

Its hind feet are large and webbed and do all the paddling, while the small front paws stay folded against the chest; out of the water those same front paws work like hands.

The world's largest known beaver dam lies in which national park in northern Alberta?

Wood Buffalo National Park hides the dam in country so remote that nobody knew it was there until 2007, when it was noticed on satellite images.

Roughly how long is the record beaver dam in northern Alberta?

850 m (2,790 ft) is its discoverer's figure, roughly half a mile, and it is recent work: photos of the site taken in 1975 show no dam there.

Why do beavers dig canals out from their ponds?

To float branches home: a beaver is awkward and exposed on land, so it digs a waterway out to its food trees and tows each load back by water instead of dragging it overland.

Where do beavers store their winter food supply of cut branches?

The cache goes in the deepest part of the pond, out of reach of other browsing animals; when ice seals the surface, the family swims out beneath it and feeds on the pile all winter.

At what age do young beavers leave the family group to become independent?

Young beavers disperse at about two years old; as yearlings they stay on to help raise the next litter before leaving to find territory of their own.

What is true of a beaver's four front teeth throughout its life?

They never stop growing, so a beaver must gnaw to keep them worn down; left unchecked, the teeth would stop its jaws closing far enough to chew, and it could starve.

What is the split 'double nail' on a beaver's second hind toe used for?

The split nail is a comb for grooming the fur: a beaver uses it to stop its fine coat matting, which keeps it waterproof and warm, and to pick out burrs and parasites.

What does a beaver's ability to close its lips behind its front teeth let it do?

Lips that close behind the incisors let a beaver gnaw underwater without swallowing water, so it can cut, peel and carry branches while fully submerged; the back of its tongue adds a second seal.

Besides steering and propping the animal upright, what does a beaver's flat tail store?

The tail stores fat: beavers eat more in autumn to build the reserve, then draw on it through the winter, when fresh food is locked away under the ice.

What protects a beaver's eyes while it swims underwater?

Transparent nictitating membranes slide across the eyes like goggles; valves in the nostrils and ears close at the same time, sealing the head like a submarine hatch.

What stops North American and Eurasian beavers from interbreeding where the two species meet?

Mismatched chromosome numbers keep them apart: North American beavers have 40 and Eurasian beavers 48, so the American beavers released in Finland in 1937 cannot blend with the native species living nearby.

By the early 20th century, roughly how many Eurasian beavers survived across the whole of Eurasia?

About 1,200 survived, in eight scattered pockets between France and Mongolia, after centuries of hunting for their fur and for castoreum, a secretion prized in medicine and perfume.

England's first licensed wild beaver reintroduction, begun in 2015, used a Devon river that shares its name with which animal?

Otter: the River Otter Beaver Trial ran for five years, and in 2020 the government let the animals stay for good, centuries after the species had been hunted out of Britain.

The beavers released into Scotland's Knapdale forest in 2009 came from which Nordic country, where the species had never died out?

Norway held one of the few beaver populations to survive in Europe; neighbouring Sweden, which had lost its own, began bringing the animal back in the early 1920s.

How many North American beavers were released in Finland in 1937, a group that grew to 12,000 within 64 years?

Just 7 animals founded the population; by the 2000s the imported species outnumbered the native Eurasian beaver across much of Finland.

Which country's government imported beavers to Tierra del Fuego in 1946, hoping to start a fur industry?

Argentina's government shipped in Canadian beavers in 1946; the fur business failed, the beavers thrived, and with no natural predators there they have felled swathes of native forest in both Argentina and Chile.

Before European colonisation, roughly how many beavers are thought to have lived in North America?

100 to 200 million is a common estimate, and some run higher; trapping for the fur trade brought the animal close to extinction, and a century of protection has rebuilt the population to roughly ten million.

For centuries, European demand for beaver pelts was driven mainly by the making of what?

Felt hats: hatters wanted the soft underfur rather than the glossy coat, because it matted into the best felt, and by the 1580s beaver 'wool' was the main raw material of French hat-makers.

Which fur-trading company, chartered in London in 1670, set the price of all its goods in 'Made Beaver'?

The Hudson's Bay Company valued everything against one prime beaver pelt, the Made Beaver, to square Indigenous barter with its own bookkeeping; it later struck brass Made Beaver tokens, and four beavers stand on its coat of arms.

Which railway surveyor designed Canada's first postage stamp, the 1851 Threepenny Beaver?

Sandford Fleming was 24 when he drew the beaver; he went on to chart a route for the railway to the Pacific and to champion the worldwide system of standard time still in use today.

What sound triggers beavers to start building or repairing a dam?

Running water is the trigger: in Lars Wilsson's 1960s experiments, beavers built over a loudspeaker playing the sound and ignored a silent leak they could plainly see.

What does a 'beaver meadow' form from?

A beaver meadow is a silted-up, abandoned beaver pond: once the dam fails the bed drains, and grasses and sedges colonise the rich sediment.

The full moon of which month is traditionally known as the Beaver Moon?

November's full moon took the name because this is when beavers finish stocking food and settle in for the cold, and it was also the season when trappers went after their thick winter pelts.

A beaver named Amik was the official mascot of which Olympic Games?

Amik was the Montreal 1976 mascot; the name, picked in a national competition, is the Algonquin word for beaver, an animal chosen because it stands for hard work.

Which waterborne illness, a risk for hikers who drink untreated stream water, is nicknamed 'beaver fever'?

Giardiasis comes from a gut parasite that beavers, among other animals, carry and shed into streams and lakes; North Americans gave it the nickname, and it is why hikers are told to treat wild water.

Tim the Beaver is the mascot of which US college?

MIT adopted the beaver in 1914 after an alumnus argued that its habits were Tech's own, praising its mechanical skill and its industry; the name Tim is simply MIT spelled backwards.

How do beavers mark the edges of their territory?

Scent mounds of mud: a beaver heaps up mud and debris and anoints the pile with castoreum, its musky secretion, a signpost its neighbours read by smell.

Castoreum, a beaver secretion, gives classic perfumes a note suggesting what?

Leather is the note castoreum lends, which is why it turns up in so many 'leather' fragrances; today perfumers nearly always recreate it synthetically instead of taking it from the animal.

How does the US Food and Drug Administration classify castoreum extract?

Generally recognized as safe is the listing, but the 'beaver in your vanilla ice cream' scare is overblown: food makers now use a few hundred pounds of it a year, against millions of pounds of vanillin.

Bäverhojt, a Swedish tradition whose name means 'beaver shout', uses castoreum to flavour what?

Schnapps: Bäverhojt is made by steeping a beaver's dried castor sacs in spirit, and Swedish hunters and trappers traditionally downed a shot of it before heading into the forest.

The extinct giant beaver Castoroides could weigh up to about how much?

125 kg (276 lb) is the upper estimate; it dwarfed modern beavers, yet its front teeth were poorly shaped for felling trees and there is little evidence it ever built a dam.

Which C. S. Lewis novel features the talking Mr and Mrs Beaver?

The Lion, the Witch and the Wardrobe: the Beavers take in the four children and tell them of the prophecy and of Aslan's return, while one of the four slips away to betray them to the Witch.

In 1948, Idaho Fish and Game moved 76 beavers into the remote Chamberlain Basin by what method?

Parachute drops in wooden boxes replaced a slow overland haul that killed many of the animals; 75 of the 76 survived, and the film of the operation was rediscovered in 2015 and posted online.

The de Havilland Canada DHC-2 Beaver, first flown in 1947, became a classic example of which kind of aircraft?

Bush plane: sturdy and able to work from short strips of land, water or snow, the Beaver became the workhorse of the Canadian North and has been called the best bush plane ever built.

The word 'beaver' ultimately traces back to an Indo-European root meaning what?

Brown is the root sense, which makes the beaver simply 'the brown one'; dictionaries usually trace 'bear' to the same root, another animal named for its colour instead of by a name of its own.

When are beavers mainly active?

Beavers are mainly active at night and at dusk and dawn, resting by day in their shelters; they do not hibernate, and under winter ice, cut off from daylight, their routine can drift out of step with the 24-hour day.

How is the beaver described because of the outsized effect its dams have on landscapes and biodiversity?

Beavers are the textbook ecosystem engineer: aside from humans, few animals do more to shape their environment, and beaver ponds filter sediments and pollutants from waterways.

In a fable of Aesop, what did a hunted beaver supposedly do to save itself?

It chewed off its own testicles and left them for the hunters, who prized them as medicine; impossible, since a beaver's testicles are internal, but the tale was repeated in bestiaries for centuries.

French cartographer Nicolas de Fer famously drew beavers building a dam at which landmark?

His 1698 map inset put them at Niagara Falls working like human builders; Europeans long imagined beavers with fish tails, tusk-like teeth and pig-like bodies.

Unlike most rodents, what do a male and female beaver typically do once they have paired up?

They stay together for life, or at least across many breeding seasons, raising each year's young as a pair; if one partner dies, the survivor finds a new mate.

Why was the beaver left off the Arms of Canada in 1921?

Its status as a rodent counted against it, and the 1921 arms went ahead without one; the beaver had the last laugh in 1975, when an act of Parliament made it an official symbol of Canada.