All About Beavers

Beavers are large, amphibious rodents who spend a major portion of their lives in or near water. They are famous for their ability to engineer and construct dams to back up streams and rivers and alter their environment to their benefit. They are revered as symbols of foresight and ambition, so much so that they are the national animal in Canada. There are two distinct species of beaver. They are the American Beaver and the Eurasian Beaver. Due to a heavy demand for their fur, which was used to make hats and castoreum, which is a musk that they secrete, in the 19th century, they were trapped and hunted to the brink of extinction. Both species are doing better today.

The following article goes into detail on the characteristics of both species, the range and environment they inhabit, and their respective life histories.

American Beaver

Description

The American beaver is the largest rodent in North America. It is also the second-largest rodent in the world, behind the capybara.

These animals look like what they are, giant rodents. They grow up to 3-feet long, excluding their tail length. They have webbed feet and dark-brown waterproof fur for an efficient swimming capability. A beaver’s teeth never cease to grow. Therefore, they have to gnaw them on trees often to keep them from growing excessively long. The American beaver has a thick layer of enamel on its teeth, which gives them an orange color.

All beavers have a pair of castors at the base of their tails. Castors are scent glands from which they use the secretions of a musk-like substance called castoreum to mark their territory.  

When you’re describing an American beaver, you can’t leave out their long, flat, black scaly tail. Their tail’s construction helps them swim and maneuver through the water more efficiently. Beavers also use their tails when they perceive danger to sound the alarm by slapping it on the water. The beaver’s tail also helps the animal on land to balance whenever they drag a heavy tree trunk or log.

Beavers can swim underwater for about 15 minutes without feeling the pressure of emerging to the surface. Also, they have transparent eyelids that facilitate them to see easily when they are inside the waters.

Range

The American Beaver lives from northern Mexico, north through the United States and Canada, where there’s sufficient aquatic habitat for them to exist. They also live in Argentina and Chile. In these two South American countries, they are classified as an invasive species, and their governments are contemplating ways to eradicate them due to the massive amount of environmental damage they are causing there.

One thing beavers are commonly known for is their ability to build dams. Actually, they are among the few animals who have the capability to change the ecosystem of the region they inhabit. They do this by blocking streams and rivers using wood and mud to create new ponds, floodplains, and lakes.

Another impressive fact about the American beaver and beavers, in general, is their capability to build lodges out of sticks, mud, and grass. Their lodges are their living quarters that can only be accessed through underwater entrances.

What they Eat

American Beavers are semi-aquatic herbivorous eaters. This means that they eat aquatic plants, but they also move from water to land to collect and eat leaves, roots, wetland plants, and tree bark.

Life History

Beavers come from a monogamous line, and they usually start mating when they are about three years old. Female beavers have an approximately 105 day gestation period between conceiving and giving birth to their young ones.

Generally, female beavers conceive and give birth to about one litter of kits per year. Their litter will range from one to four kits. Beaver kits nurse for about two weeks. Together with the ones born before them, new kits live harmoniously with their parents inside their lodge. Young beavers leave their parent’s lodge and strike out on their own when they are around two years old.

Eurasian Beaver

Description

At first glance, the Eurasian Beaver looks a lot like its American cousin. There are some differences between the two species, though. Eurasian beavers have larger, less rounded heads with longer, narrower muzzles. They also have longer nasal bones, with the widest point being at the end of the snout; in the case of the North American beaver, the widest point is at the middle of the snout. The Eurasian beaver has a triangular nasal opening, unlike those of the North American beavers, which are square. Their tails are narrower than those of American Beavers, and they have shorter shin bones. The guard hairs of the Eurasian beaver have longer hollow medullae at their tips. One last difference that isn’t readily apparent to the eye is that the Eurasian Beaver has 48 chromosomes while the American Beaver has 40.

Like the American Beaver, the Eurasian is also one of the largest living rodent species. They are the largest extant rodent in either Europe or Asia. From the top of its head to its tail, an adult animal measures 31-39 inches long. Additionally, their tails measure 9 1/2 –19 1/2 inches long. They weigh anywhere from 24–66 lbs, with the largest recorded weighing in at 70 lbs.

Range

Eurasian Beavers are native to the European and Asian Continents. Like the American Beaver, the Eurasian Beaver population suffered because of the demand for their fur and castoreum. They were expatriated from much of their native range in the 19th century and extinct from Great Britain 200 years earlier through unregulated hunting and trapping. Today though, they have been reintroduced to much of their native territory. In Europe, Eurasian Beavers exist in much of Scandinavia, Russia, Spain, France, Germany, and Poland. Beavers have also been reintroduced in the United Kingdom. In Asia, there are beaver populations in China and Mongolia.

These beavers can be found in areas with access to water throughout the year. Like their American counterparts, the Eurasian beavers customize different habitats to suit their needs through dam building.

What They Eat

The diet plan of Eurasian beavers isn’t that different from American beavers.

These animals are herbivorous. They consume aquatic and riverbank plants. They also eat stems, twigs, buds, and bark from trees. Their digestive system is uniquely adapted for the utilization of tree cellulose. Their long appendices and the microorganisms they contain make this possible. They take in approximately 20% of their body weight daily.

Life History

As for reproduction, the Eurasian beaver usually breeds from December to April and gives birth to litters of 1-3 kits. The young usually start to learn swimming in a matter of hours. Eurasian Beaver kits are weaned when they are around six weeks old.

They remain with their parents until they are around 2 years old, though. When beaver kits are around 3 years old, they seek out a monogamous mate and start a colony of their own.

Interactions With Humans

Fur And Castoreum

As has been eluded to, demand for their fur and castoreum led to population decimation in both beaver species. From the late 16th century through the mid 19th century, hats made from beaver felt were an important fashion accessory. Castoreum was used in perfumes and medicines. It was also used as a flavoring in foods. In the mid-19th-century, fashion trends in Europe shifted away from beaver-felt hats. As a result, demand for beaver fur dried up. With no market demand, trapping also essentially ceased.

By the early 1900s, countries began to reintroduce these animals to their native habitat. Today the American Beaver population is thriving. Eurasian Beavers are coming back as well. The biggest Eurasian Beaver population is in Russia.

As of 2021, there is still some demand for beaver pelts and castoreum. Castoreum is an ingredient in some perfumes. It is also a flavor enhancer. Your favorite vanilla ice cream might well contain castoreum. Raspberry and strawberry flavored products also sometimes contain castoreum. Castoreum is also an ingredient in some natural health remedies.

We won’t run out of beavers, though. Harvesting of these animals is a regulated activity. Trappers aren’t allowed to take more than the population can replenish.

Argentina And Chile

In 1946 The Argentine Government introduced beavers to Tierra del Fuego with the thoughts that they would establish a fur industry in that area. The fur industry never materialized, but with no natural predators, the beaver population has exploded. The animals devastate areas of forest. They then move on when the resources in the area they’re in are exhausted. The animals have also moved onto Chile’s Brunswick Peninsula. The governments of both countries are exploring ways to rid themselves of beavers.