International Beaver Day is April 7th!

Feature photo above by Jennifer Howard

By Elizabeth Trickey

Beaver chewing down a tree by D. Gordon E. Robertson

Here I am, beavering away, writing yet another article for the Procyon Post!  These chubby, furry rodents that we celebrate on April 7th, do live up to their reputation.  They are hard at work, all year-round, not just foraging for food, but building natural structures that benefit the ecosystem.  OK, and chewing down a tree or two at your cottage, but, please, that’s their job! 

There are only 2 species of beavers in the world, and North America is lucky to have the Castor Canadensis.  It’s cousin, the Castor Fiber, lives in parts of Europe and Asia.  Although both species are very similar, this article will refer to the ones on our own continent.  Humans killed millions of these animals, mostly for their fur, but also for food and medicines.  For centuries, they were over-hunted, coming close to extinction, before laws came into effect to protect them.  Even though beaver populations are now thriving, there are substantially fewer of them.  Today, there are approximately 15 million of these critters, far fewer than the estimated 100-200 million that existed before the fur trade.

Photos above are of the North American (Castor canadensis) and it’s cousin, the Eurasian (Castor Fiber) beavers.

Giant Beaver compared to modern-day Beaver Illustration by Dorothy S. Norton.

The beaver is the largest rodent in North America.  Including a tail that is about a foot in length, this animal is 35-50” long and can weigh anywhere from 35-70 pounds.  If you think this is large for a rodent, be thankful you didn’t live 12,000 years ago in the Ice Age.  Beavers, then, were huge, being 8 feet long and weighing almost 200 pounds!  That’s about the weight of a medium-sized black bear!

Because beavers spend so much time in the water, their bodies are adapted to it.  When swimming underwater, a thin, transparent membrane closes over their tiny beady eyes, protecting them like swim googles, and their ears and nostrils, which are also small, are closed off.  To aid in swimming, their large back feet are webbed and their tails are scaly and flat, acting as rudders.  They are also able to close their lips behind their teeth while under water so that they can chew and carry branches while submerged.  Unfortunately for the beavers, they have a most beautiful colour of reddish-brown fur that is thick and waterproof.  It almost led to their demise on Earth!  But it’s good for them because it keeps them warm and dry.

Photos above show the beaver swimming underwater.

Fore foot, hind foot, and tail of a beaver by Mary E.C. Boutell
Split claw by Janet Pesaturo

The hind paws of a beaver are much bigger than the forepaws, and have 5 long, blunt claws on each webbed foot.  The front feet are used for different purposes, so they are small and have sharp claws for digging.  They aren’t webbed, and are kept in close to its body when swimming.  These paws are quite dexterous, being used to pick up and carry items, and to perform many building tasks.  Both front and back claws help to keep the beaver well-groomed.  One of the toes on the hind foot has a double claw that is hinged and they work like mini pliers to pick mites, insects, and unwanted bits out of its fur!  This preening is not just so that it looks good for mating purposes or photo ops, but it is necessary for the beaver to distribute oil, from the glands near its anus, all throughout its pelt to keep it waterproof.  Often, family members will groom each other.

Beaver Teeth

Other features for this animal include huge front teeth which are constantly growing.  Their chompers are about an inch long and are used regularly, so they wear down after all the chewing, and need to be replenished.  So these animals not only wear down their teeth by chewing, but actually need to chew since the teeth grow no matter how much or how little they do it.  How much do they grow?  A whopping 4 feet per year!  Oh, chubby beaver, you better get gnawing!  Interestingly, if you’ve ever seen a beaver, you might have noticed that its teeth are an orange colour.  That isn’t a result of not using a good toothpaste, it’s because they have iron in their enamel!  Iron is a very strong substance, and it takes a strong tooth to chew down a tree.  Another fascinating fact about these chompers are that the back of the teeth do not have enamel.  Instead they have a substance called dentin which is softer and wears down faster.  This way the back of the teeth erode faster, leaving a knife-like, sharp edge for chewing on the tough tree bark.

Beaver tail by Jennifer Howard

If you want to learn more about beaver tails, be careful when you google them.  You might think they are for sale as a tasty treat!  No, real beaver tails are filled with fat and muscle and are surprisingly flexible, yet strong.  Besides being used for propulsion and to steer when swimming, beavers use them on land as a support to sit and stand.  As well, although beavers are graceful swimmers, they are somewhat awkward on land, and the tail helps them to balance when walking on their hind legs.  When the cold weather approaches, these animals store extra fat in their tails in case more sustenance is needed to get them through to spring.

Beavers have very good hearing, as well as a strong sense of smell and a delicate touch, but their sight is poor.  Their vocalizations include whines (pleasant family greetings or kids needing something), hisses (when they’re angry), and growls (for defence), but they also communicate through physical means.  Besides slapping their tails in water as a warning, they will leave mud pies on their paths with their paws prints as well as a secretion of musky oil from their scent glands.  With their short legs and round body, they are not very adept moving on land, so they are easy pickings for predators.  So these critters prefer to dig canals in wetlands which are deep enough to swim in and move logs down.

Dam in Algonquin

Although beavers do build dams, they do not live in them.  They live in homes called lodges which are built close to the water.  First, dams are built to ensure that there is a deep water source that will not freeze during the winter months.  These animals use the deep water to transport large tree trunks and stems to the lodge where they store them for their winter food.  And if predators come calling, the water acts as a quick underwater get-a-way.  Dams are typically made with logs, branches, leaves, mud, and rocks at the narrowest part of the river where it is moving fastest.  The beavers place the branches very deliberately, weaving them together, and allowing the moving current to push them snuggly into place, then they add leaves and mud into empty spaces, forming a very solid base.  They continue to build up the structure by attaching several layers on top.  Some dams have been discovered to be up to 18 feet high!  They are not only solid and strong, but are also regularly maintained by these busy and industrious rodents.

Once the dam has been built, a beaver will work on building its home.  It uses the same supplies as it did for the dam and takes about a month to construct.  A beaver begins by making sure the base of the lodge is several inches above the water line so its inhabitants can stay dry.  It makes a sturdy dome of sticks, leaves, and mud, leaving a ventilation hole at the top.  Inside the lodge there is a dining room, bedroom, areas where there is some fresh air, and usually 2 entrances/exits, built for drying off and safety.  Sometimes beaver colonies will have 2 lodges, one for summer (the cottage!) and one for winter.  Occasionally, a beaver might find an abandoned lodge and build onto it.  An extra wing for the kids!  Sure, beavers are very social animals within their own colony, they mate for life, and lodges often house about 8 of the critters, so there needs to be space for everyone. 

Lodge in Ontario
Lodge with beavers on it by Enrique R. Aguirres.

The average lodge is 20 feet across and 10 feet high, but does depend on how many beavers are living there.  Most of this building happens between dusk and dawn since beavers are nocturnal animals.  They chew down over 200 trees every year, some of them more than a foot in diameter.  If a tree is quite large, they work in pairs to get it down.



Since these critters are active all winter, they bring food to the entrance of the lodge so they don’t have far to go when they get hungry.  They will stick branches deep in the mud at the entrance to their home so the edible parts stay easily accessible.  At the top of this food pile they put branches that they won’t eat.  These branches end up above the water line, which freeze and trap snow so that it insulates the edible food.  Those rodents sure are smart engineers!  Beavers are herbivores, eating both terrestrial and aquatic plants.  They eat stems, roots, bark, leaves, grasses, fruit and some crops like corn and beans.  Preferred trees are poplar, aspen, birch, willow, maple, and black cherry.  Their summer diet is more herbaceous due to availability, while a winter diet tends to be more woody.  When the water is frozen over, they not only have their food cache, but will also gnaw on the roots and stems of aquatic plants such as the bulrush and pond lily.  Because beavers eat so much greenery, which is difficult to digest, they engage in coprophagy, which is eating their own poo.  The first bits of poo that are eliminated are soft and green, still containing many nutrients.  So they give these little morsels another round in their digestive systems.  Sounds delicious!

Beavers do mate for life.  Their foreplay involves playful wrestling, and they breed, usually in the water, during the winter.  Gestation is 3 and a half months, and shortly before birth, Papa is sent packing, taking up residence nearby, in a burrow or in an abandoned lodge, until after the kids are born.  Mama prepares a nursery in the lodge for the newborns, usually 2-4 babies, called kits, which are born weighing about a pound (just envision a pound of butter and put a flat tail at the back of it!).  They can already see, walk and swim, and have teeth and fur.  Although they are weaned in just a few weeks, the babies stay with their parents for a couple of years.  They remain within the lodge for the first month then gradually leave its safety, under Mama’s watchful eye, learning all the skills a beaver needs.  Papa and older siblings also take part in the care and learning of the kits.

In the lodge, there will be the 2 parents, and kits from the 2 most recent years.  The babies do not work in their first year, structural engineering degrees taking a bit longer to get.  When the babies are in their second year, they are expected to help around the lodge, learning the skills of meal preparation, roof repair, and general lodge and dam maintenance.  When the 2 year old kits leave the parental home, they build their own lodges and begin searching for a mate, being able to breed in their third year. Depending on the availability of food in the area, these critters may live in their lodges for their entire life, which is about 20 years.

Female beavers are the boss in the family core.  When kits venture out for the first time in the spring, it is also the time when many of their predators are out hunting after a long, cold winter.  So Mama careful guards them, and if she perceives any threat, she will quickly pick them up in her mouth and whisk them off to the nearest burrow.  Beavers will aggressively defend themselves by standing on their back legs, hissing and growling, and will lunge and bite the other animals.  When swimming, they warn others about imminent danger by smacking their tails on the water which makes a very loud noise, hopefully scaring away predators, which include the coyote, wolf, cougar, bear, wolverine, otter, lynx, eagle, hawk, owl, and human.

Beavers are animals that are under-appreciated for all that they do for our world.  People do get frustrated when they chew down trees on their property, and once lodges are abandoned, the nearby dam no longer gets the maintenance it needs so can burst.  That happened at our cottage in Haliburton.  Rumour had it that a cottager relocated the beaver family due to a few trees being chewed down on his land.  The dam eventually burst and the little creek became a rushing river, over 20 feet wide!  It swathed quite the path through the forest and took out the road, stranding cottagers and their cars on the other side.  The next day, the water was still draining from the wetland and our usual clear lake was a murky mess!  Nobody was hurt, just inconvenienced, though after that, my daughter and I always did the climb through the forest, up to the swamp, with a new respect for nature.

It is unusual for beaver dams to deteriorate and burst like that.  Dam building has many positive effects in our world like creating wetlands for other species to thrive, preventing erosion, altering river flows, and storing water so that droughts don’t create as much devastation as they might have.  Dams also help to purify the water by raising the water table which breaks down toxins.  Salmon and trout benefit from the damming since that is where they will go to eat, spawn, and over-winter.  The altered gases create a chemical change that allows for new species to appear in the area, like frogs and turtles that prefer the warmer water as their habitat.  As the old forest slowly decomposes, it gives life to a meadow and all the animals in it.  Researchers in hydrology are only now realizing how extensive the benefits of damming are in preserving our wetlands, and have even suggested that we should recruit some of these tree-chewing engineers to aid in wetland rehabilitation projects!

Not long ago, people benefitted too much from beavers.  When beaver hats were the must-have in fashion, 200 000 pelts per year were sent over the pond to Europeans.  Eventually demand for this fashionable item dwindled, perhaps because at this rate, most rich people already owned one, and also because the beaver population was diminishing to the point where many regions no longer had any.  People only seemed to realize that this was major problem after there were hardly any beavers left.  A man named Grey Owl, with his 2 beaver friends, Jelly Roll and Rawhide, led the charge, with writings, lectures, and even a short film, to save the beavers.  It was at this time that governments finally listened and outlawed trapping until these animals were no longer at risk of extinction.

Grey Owl feeding his beaver, Jelly Roll from Canadian National Railways. Library and Archives Canada

Many sayings and attributes recognize the value of beavers – work like a beaver, busy as a beaver, to beaver (always work hard), beaver intellect (slow but honest), eager beaver, beaver away (work a long while at something).  Folklore is pretty much the same, with the beaver as a symbol of persistence, hard work, and productivity.  So it does seem rather incongruous that on April 7th when we are celebrating these tireless, determined animals, on the same date other people are celebrating “No Housework Day”.  I’ll bet the beavers won’t be celebrating that!

Canada first stamp the Three Pence Beaver Stamp of 1851
Sculpture over entrance to the Parliament Building by D. Gordon E. Robertson

More than any other animal, the beaver has been been instrumental in Canada’s history.  Europeans, in the search for beaver pelts, were drawn to Canada to hunt and live.  This toothy, talented rodent became our national symbol which is seen on the first picture stamp (the Three-Penny Beaver), our nickel, guarding the entrance to the parliament buildings, the logo for Parks Canada, and often in advertising.  As I think about this amazing, industrious engineer of ours, I am reminded of the Canadian senator, about 10 years ago, who tried to get our beaver replaced by a polar bear as the emblem of Canada.  Her argument was that we should not be represented by a “dentally defective rat” and “toothy tyrant” that wreaks havoc (did I mention she owned a cottage and this was a personal grudge against beavers?).  She obviously was ignorant to its talents, and benefits to our country’s ecosystems.  And as someone who sports an overbite, I take great offence to her remarks!  However, I always look at the source and find her reasoning rather ironic.

Here are a few interesting nuggets of information about the beaver:

Beavers have scent glands, called “castors”, which are found in the same general area as their anal glands, and they secrete a slimy, brown substance, castoreum.  These 2 glands work together to produce an odour which is used to mark their territory.  And you might think “P.U”!!  Except humans really like the smell and actually use it in manufacturing many different perfumes.  And evidently, humans also seem to think that it is good to eat because it has the delicious flavour of vanilla.  And eat it, we do.  In ice cream, gum, baked goods, sleep aids, pain meds, candies, drinks – and don’t try to look for it on the ingredient list of your favourite foods since it is only listed as “natural flavour”.  Yum, yum!  However, if you really want to taste that gooey brown slime, I understand that a Swedish company proudly uses it in their schnapps – Beaver Shout.  And, no, that castor oil you were made to have as a kid didn’t come from a beaver’s castor sac.  That is made from castor beans.  Phew!

Close to that area of the body is another story – a tall tale based on the critter’s anatomy.  You see, a beaver’s testicles are inside its body, and long ago, a myth was created that the beavers chewed them off so hunters wouldn’t kill them.  And people actually believed that story for hundreds of years!

As a retired skydiving instructor, I was tickled pink to read that 76 beavers made the big leap.  Back in 1948, before my time, when beavers were still a threatened species, humans in Idaho didn’t want the beavers in their area.  So the government decided to relocate them – the beavers, not the humans.  They found a protected, out-of-the-way area in the state, so remote that the only way to get them there was to drop them in from a plane!  So they boxed up the beavers, tied military parachutes to the boxes, and sent those rodents flying.  I wish I was there!  75 of those furry daredevils got their wings.  Unfortunately, one beaver bit the dust.  Heavy sigh.

Beavers are important in our country and we need to acknowledge the service they perform and respect their space.  In coming years when we are hit by droughts, we will be relieved to know that the work that these animals have performed in our ecosystem are helping us to make it through the tough weather times.  So on April 7th let’s raise a glass to the beaver, and leave our housework for another day!

I’ll leave with a few corny jokes:

What did the river say when it saw beavers for the first time?
“Well I’ll be dammed!”

Two beavers were standing at a river’s edge, looking at the view. 
One said to the other, “Dam it!”

What does a French beaver call her handiwork?

A rabbit and beaver are admiring the majesty of the Hoover Dam.
The beaver turns to the rabbit and says,
“Well I didn’t build it, but it is based on my design!”

What did one beaver say to the other when he fell into the river?

International Beaver Day is April 7th!
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