Canada: Busy beavers a national asset

Photo of Mark Thornton

Canada’s furry national symbol is the ultimate "wild earth guardian".

The beaver is Canada’s national symbol, officially representing the country since 1975, with good reason. It’s recognised as a keystone species, one that has a disproportionately beneficial effect on its environment relative to its numbers. It’s revered in the United States too, where some refer to it as a “wild earth guardian”.

A significant ameliorator of climate change in their habitat, beavers are included as major players in the US Forest Service climate change adaptation strategy, which advocates reintroducing them to any habitat from which they have disappeared due to human interference. Foresters recognise beavers as the only animals able to completely transform a landscape, other than ourselves, and acknowledge that more than half of North America’s threatened or endangered species rely on wetlands created by beaver dams for survival. They have natural value almost beyond imagining.

I have become familiar with several beaver families in north-western Canada during the past 15 years. In late summer I visit one of my daughters, who lives near Atlin, an isolated gold-mining village with a population of 450. It sits on the edge of Atlin Lake in British Columbia, one of many vast lakes bordering the Yukon Territory fed by almost numberless rivers and streams inhabited by beavers. Most days I fish these wilderness waterways for trout and Arctic grayling, and rare is the day I don’t see a beaver.

A favourite spot is Pine Creek, which drains Surprise Lake, east of Atlin. The creek is full of Arctic grayling, tasty fish that readily take an artificial fly fished dry or wet. Fly fishing is a quiet, unobtrusive activity. Usually, within 20 minutes of my arrival at the creek, any animal that might have hidden from me senses no threat and returns to its normal business. These animals include a resident osprey, bald eagles, brown and black bears, otters and a family of beavers, often including several young, known as kits.

With their 35cm-long flat, paddle-shaped tails, big webbed hind feet and unwebbed front claws for digging, beavers are perfectly suited to their aquatic lives, developed over 12 million years of evolution. Their eyes have an extra retractable lid, allowing them to see well underwater, and they can close their nostrils when submerged. They are industrious and while they prefer the cover of darkness or twilight to work on their dam or collect leaves to eat, when there are no threats they will venture out during the day.

Part of a dam is built up into a dome, called a lodge, where two adults and up to six kits live, warm and snug above the water line. For protection against predators, the entrances (usually at least two) are below the waterline. Every couple of hours, I would see a beaver motoring up or down the creek, often towing a leafy branch considerably bigger than itself. Sometimes one would swim up to within 2m of me to see if I was a threat. After a minute or so, satisfied I wasn’t, it carried on beavering about.

On two occasions, one sensed something about my presence it didn’t like and smacked its tail on the surface of the water, a common warning gesture. But the challenge showed it wasn’t afraid. There are many stories of dogs attacking beavers only to be dragged into the water and drowned. Once I watched my daughter’s dog Smokey, a Canadian-bred Australian blue heeler, attack a beaver. She hauled him off before the beaver, which was bigger than him, could drag him into the river.

Infrequently hungry brown and black bears, lynx, mountain lions and wolverines will attack a full-grown, 30kg beaver if they can catch it by surprise out of the water. Once it’s in its element, though, even the bigger predators are less likely to attack. The biggest threat comes from humans, not from hunting so much as destruction of habitat.

Before the arrival of Europeans, there were about seven million native people in North America. They hunted beavers for their fur but only killed enough for their own needs. The beavers numbered in hundreds of millions and lived from the Arctic tundra to the deserts of northern Mexico and from the Atlantic to the Pacific oceans. Then the French and English arrived and found a new source of materials for their luxury clothing, felt and hat industries. More than 50 years before the 1849 California Gold Rush, there was a California Fur Rush, which targeted beavers and sea otters, driving the earliest American settlement in that State.

The hunters soon found that the best pelts came from regions where beavers grew thicker fur because winters were severe, so most of the hunting took place in Canada. Apart from providing warmth for the wearer, the beaver’s fur has two layers; a thick outer layer and an inner one of fine hair that, together with a substance called castoreum produced by a gland near its tail, provides the waterproof barrier that keeps its skin dry underwater. So for humans, the fur was functional as well as fashionable. 

Having killed most of their own native beavers, the Europeans, with help from the willing Native Americans whose local knowledge was invaluable, established an industry that hunted the semi-aquatic rodents nearly to extinction over more than 200 years. Thankfully their numbers are rebounding but now, at 15 million, are still only a fraction of what they were. Beavers are common in the more remote parts of the north and with patience, common sense and a bit of diligent reading of a river valley’s terrain, you would be unlucky not to find at least one lodge.

Despite their inestimable value to the ecosystem, it is not illegal to hunt or trap beavers and more than 135,000 are still killed legally each year by hunters specifically for their fur. A smaller number are killed as pests because their dams cause flooding and damage to roads, agricultural lands and property. Yet most naturalists, including those in government agencies, know beavers do far more good than harm.

Beavers, which mate for life, play a critical role in maintaining the structures of ecological communities. Trumpeter swans and Canada geese both often depend on beaver lodges for protection. Rather than nesting on large lakes, they prefer smaller lakes and ponds associated with beaver activity, often nesting on top of a lodge. Ornithologists believe they derive protection in some way from the beavers’ presence. Beavers don’t seem to mind at all.

Beaver dams are built across streams out of branches, sticks, rocks and mud. They create big ponds and wetlands that increase the numbers and diversity of plants, invertebrates, fish, mammals and birds. Feeding on riverside plants also enlarges the riparian zone between land and water, encouraging a greater variety of animal habitats. The dams provide water around their lodges that is deep enough not to freeze solid in winter, so the beavers can enter and exit year round. This creates areas of open water, allowing birds to nest earlier. A Wyoming study found watercourses with beavers had 75 times more ducks than those without.

The deep, ice-free beaver ponds also help to increase trout and salmon populations that would otherwise freeze in winter. Researchers in Washington State found that extensive loss of beaver ponds on the Stillaguamish River, one of the most famous trout and salmon rivers in the western United States, reduced numbers of coho salmon by 90 per cent.

Beaver’s dams can be huge. The largest, 850m long, was discovered in 2007 using satellite imagery in Alberta. Building dams requires a great deal of wood chewing so beavers’ sabre-like front teeth never stop growing. They don’t actually eat the wood, just the bark, and prefer aspen and poplar but also birch, maple, willow, beech and occasionally pine and spruce.

Despite repeated claims by naturalists that river otters do not attack beavers, I once saw a family of otters attack a beaver lodge on Pine Creek. It was a sustained effort by five otters, but they were driven off, snorting and barking, after five minutes. It’s certainly an unusual event because beavers are twice the weight of otters. The Canadian Journal of Zoology has reported hunters describing otter attacks in Alberta and a 1994 river otter study reported finding beaver remains in 27 of 1191 scats analysed. 

Such is the value of beavers to Canada that they are honoured on a five cent coin and a postage stamp, the first stamp to show an animal rather than a head of state. Several States publish booklets on how to encourage beavers to restore streams. 

So it’s surprising that beaver hunting is still permitted, even though there are some restrictions. The Canadian Association for the Protection of Fur-bearing Animals has urged greater restrictions on hunting, saying: “We think this is no way to treat our wildlife, let alone our national symbol” — a statement with which I most heartily agree.


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