60 Fun Facts About Beaver

Beavers are the second-largest living rodents. Which animal is the largest?

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 crack carries a long way over water and usually sends the whole family diving.

What kind of eater is a beaver?

Bark, twigs, aquatic plants and sedges are the menu; the fish are just neighbours in the pond.

What are baby beavers called?

Up to four are born each spring or summer after a three-to-four-month gestation.

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?

The entrances are underwater, which is why beavers need a pond deep enough not to freeze solid.

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

The English word beaver, by contrast, descends from Old English beofor.

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

Typical dives are far shorter, five or six minutes, and its heart rate halves while it is under.

How fast can a beaver swim?

Webbed hind feet do the work; the tail acts as a rudder rather than a paddle.

While diving, a beaver's heart rate drops to about how many beats per minute?

That is half its normal rate, and on surfacing it can swap out three-quarters of the air in its lungs in a single breath.

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

It sits in a remote corner of northern Alberta and was spotted on satellite imagery before anyone had walked to it.

Roughly how long is that record beaver dam in Alberta?

NASA imagery shows it did not exist in 1975; generations of beavers have been adding to it since.

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

At the base it measured seven metres thick, sturdier than many human levees.

A study in Poland found beavers could rebuild a destroyed dam and restore water levels in about how long?

Which is why simply tearing out a dam rarely solves a landowner's flooding problem.

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

Thicker trunks of 25 cm or more can keep a beaver busy for hours.

A beaver lodge sturdy enough to survive the coming winter can be finished in as little as how long?

Experienced families build much bigger ones, up to two metres high and six metres across above the waterline.

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

Submerged wood stays fresh and reachable under the ice when the family cannot leave the water.

Beavers live in monogamous family groups. At what age do young beavers become independent?

Yearlings often stay on to help raise the next litter before dispersing 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.

The second toe on a beaver's hind foot carries a split 'double nail'. What is it for?

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

A beaver's lips can close behind its front teeth. What does this let it do?

The back of the tongue rises to make a second waterproof seal.

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

A countercurrent blood system in the tail also dumps excess heat on hot days.

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

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?

North American beavers carry 40 chromosomes, the Eurasian species 48.

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

They clung on in just eight scattered populations between France and Mongolia.

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

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?

The imported species now outnumbers the native Eurasian beaver in much of Finland.

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

The fur business failed but 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?

Today's population of 10 to 15 million is a fraction of that, though a huge recovery from the near-zero of 1900.

How many beaver pelts a year did the Hudson's Bay Company buy at the fur trade's 1860s peak?

Protection laws in the late 19th and early 20th centuries came just in time for both species.

The 'made beaver' was the Hudson's Bay Company's unit of account. In 1795, how many bought a gun?

One made beaver equalled one prime winter pelt from a male, and would also buy eight knives or a kettle.

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

By the 1580s beaver 'wool' was the main raw material of French felt-hatters, and the trade had already emptied 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?

Fleming is better known for proposing worldwide standard time zones.

The 1851 Threepenny Beaver was the first official postage stamp anywhere to picture what?

Every earlier official stamp had shown a monarch or head of state.

In what year did the beaver first appear on Canada's five-cent coin?

During the Second World War it was briefly replaced by a 'Victory' design with a Morse code message on the rim.

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

The Canadian horse joined it as an official national animal in 2002.

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

Amik means beaver in Algonquin; the name was chosen through a national competition.

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

The obverse carries the state seal; the beaver has been on the back since the flag was adopted in 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.

MIT's mascot is a beaver called Tim. Where does the name come from?

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?

It spread across Scouts Canada the following year and later to 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 was the loophole; 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?

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?

Historically it flavoured strawberry and raspberry products and vanilla substitutes, though the whole industry now uses only about 100 kg a year.

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

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?

It was 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?

Castoroides ohioensis 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?

Seventy-five survived the drop; the film of the operation was rediscovered in 2015 and posted online.

What was the nickname of the beaver used to test the drop boxes for the 1948 Idaho relocation?

Employee Elmo Heter built the boxes from surplus Second World War parachutes.

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

The same root gives the animal its name across most European languages.

When are beavers mainly active?

They do not hibernate, and in far northern winters their activity even drifts off the 24-hour clock into 'days' as long as 29 hours.

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

Aside from humans, few living animals do more to shape their environment; beaver ponds also 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?

He showed them 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.