55 Fun Facts About Beaver

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

The capybara of South America can top 60 kg; a big beaver reaches about half that.

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

The iron-hardened enamel sits on the front of the incisor, so the softer back wears faster and keeps the edge chisel-sharp.

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

The slap is a warning to other beavers of danger: the crack carries a long way over water and usually sends the whole family diving for cover.

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; a litter of one to four is born each spring or summer after a gestation of roughly 105 days.

The beaver sits on a rock on the reverse of which Canadian coin?

The G. E. Kruger Gray design has been on the nickel since 1937.

Which US state is nicknamed the Beaver State?

The beaver is also Oregon's official state mammal and the mascot of Oregon State University.

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

Beavers build lodges; the entrances are underwater, which is why they need a pond deep enough not to freeze solid.

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

Castor comes from the Greek kastor, the word for beaver; Latin borrowed it and Linnaeus used it as the genus name in 1758.

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

A beaver can stay under for up to 15 minutes; typical dives last five or six, and its heart rate halves while submerged.

How fast can a beaver swim?

Beavers swim at about 5 mph (8 km/h): the webbed hind feet do the work, and the flat tail acts as a rudder rather than a paddle.

The largest known beaver dam in the world is in which protected area?

Wood Buffalo National Park in northern Alberta holds the dam; Jean Thie spotted it on satellite imagery in 2007 before anyone had walked to it.

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

The Wood Buffalo dam runs about 850 m (2,790 ft); it is absent from 1975 aerial photos, so generations of beavers built it in a few decades.

A 652-metre beaver dam, 4.3 m high, was found near Three Forks in which US state?

The Three Forks dam in Montana was seven metres thick at the base, sturdier than many human levees.

How quickly can a beaver fell a tree about 15 cm (6 in) thick?

A beaver can drop a 15 cm trunk in under 50 minutes; thicker trunks of 25 cm or more can keep it busy for hours.

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

The cache goes in the deepest part of the pond; submerged wood stays fresh and reachable under the ice when the family cannot leave the water.

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.

In the wild, beavers usually live up to about how many years?

Wolves, coyotes, big cats and bears are the main predators of adults.

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, which keeps the dense coat waterproof; a beaver's pelt packs up to 23,000 hairs per square centimetre.

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

Lips sealed behind the incisors let a beaver gnaw underwater without swallowing water; the back of the tongue rises to form a second waterproof seal.

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

The tail stores fat for winter; a countercurrent blood system in it also dumps excess heat on hot days.

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 did more than 27 Russian attempts to hybridise North American and Eurasian beavers produce?

The only result was a single stillborn kit: North American beavers carry 40 chromosomes, the Eurasian species 48, so the two cannot interbreed.

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

About 1,200 survived, clinging on in just eight scattered populations between France and Mongolia.

By 2020, the Eurasian beaver population in Europe had recovered to what level?

More than one million: reintroductions across the continent turned one of Europe's rarest mammals into a common one within a century.

The beavers released into Scotland's Knapdale forest in 2009 came from which country?

Norway had kept one of the few beaver populations that never died out in Europe.

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 about 50 Canadian beavers in 1946; the fur business failed, the beavers thrived, and with no bears or wolves to eat them they have felled swathes of native forest.

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

Estimates put the pre-contact population at 100 to 200 million; by 1900 it was near zero, and the 21st-century recovery stands at roughly 10 to 15 million.

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

Felt hats: by the 1580s beaver 'wool' was the main raw material of French felt-hatters, and demand had already stripped most of western Europe's rivers of beavers.

Why did the North American beaver fur trade go into steep decline from the 1830s?

Silk top hats took over, and the beaver got its first real reprieve in two hundred years.

Who designed the Threepenny Beaver of 1851, considered Canada's first postage stamp?

Sandford Fleming, the engineer later famous for proposing worldwide standard time zones, drew the beaver design for the 1851 stamp.

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

Running water is the trigger: in Lars Wilsson's 1960s experiments, beavers piled sticks and mud over a loudspeaker playing a trickling stream, even on dry ground.

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.

In what year did Canada officially declare the beaver a national animal?

The National Symbol of Canada Act made the beaver official in 1975; the Canadian horse joined it as a national animal in 2002.

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

Amik was the Montreal 1976 mascot; the name means beaver in Algonquin and was chosen through a national competition.

What colour is the beaver on the reverse of Oregon's two-sided state flag?

The reverse shows a gold beaver on navy blue; the obverse carries the state seal, and the two-sided design has flown since 1925.

Besides the Beaver State, which state has the North American beaver as its official state mammal?

The beaver also appears on the seal of New York City, a nod to the fur trade that founded it.

Where does the name of MIT's beaver mascot Tim come from?

Tim is MIT spelled backwards; the beaver itself was adopted in 1914 because beavers are 'nature's engineers'.

The Beaver Scouts programme for young children was designed and tested in 1971 in which city?

Winnipeg ran the 1971 pilot; the programme later went national across Scouts Canada and reached the UK, where Beavers wear turquoise.

The medieval Church's ruling that the beaver was part fish allowed people to eat its tail when?

The scaly tail counted as fish on meatless Fridays and in Lent; the same logic was applied to capybara in South America.

Castoreum, the beaver's scent-marking secretion, is used in perfumery mainly for a note suggesting what?

Castoreum lends a warm leather note; it is extracted with alcohol from the dried castor sacs and blended as a tincture.

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

The FDA lists castoreum extract as generally recognized as safe; it historically flavoured strawberry, raspberry and vanilla products, though by 2007 annual use had fallen to roughly 300 lb.

In Sweden, castoreum traditionally flavours a variety of snaps known as Bäverhojt, a name meaning what?

Bäverhojt means 'beaver shout'; salicylic acid from the willow and aspen bark beavers eat is thought to give castoreum its character.

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

Castoroides weighed up to about 125 kg (276 lb), roughly black-bear sized, with 15-cm incisors, yet there is no evidence it ever built a dam.

Giant beaver fossils were first discovered in 1837 in a peat bog in which US state, giving the species its name?

The 1837 Ohio find gave the species its name, Castoroides ohioensis; it died out at the end of the last Ice Age, overlapping with the first humans in North America.

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

They were parachuted in wooden boxes; seventy-five survived the drop, and the film of the operation was rediscovered in 2015 and posted online.

What was the beaver that tested the crates for the 1948 Idaho relocation nicknamed?

Geronimo was loaded and released again and again to test Elmo Heter's self-opening crates before being set free with three females.

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

The root is *bher-, 'brown', so the beaver is 'the brown one'; the same root names the animal across most European languages.

When are beavers mainly active?

Beavers are mainly active at night and at dusk and dawn; they do not hibernate, and under winter ice their rhythm drifts into 'days' as long as 29 hours.

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.

According to an old fable of Aesop, what did a hunted beaver supposedly do to save itself?

Impossible, since a beaver's testicles are internal, but the myth about castoreum persisted 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.

How do the nasal cavities of the Eurasian beaver differ from those of its North American cousin?

The Eurasian species is also slightly longer, with a more elongated skull, lighter fur and a narrower tail.

Why was the beaver passed over for the Arms of Canada in 1921 despite its national symbolism?

It still made the five-cent coin, the Hudson's Bay Company arms and the logos of Parks Canada and Roots, and became the national animal in 1975.