What's brilliant about Beavers
By Noah Patton
In our efforts to understand the amazing critters of our world, we turn our eyes this week to the beaver. No other animal works as hard as this wonderful rodent or takes as much pride in the efforts of their labour…
Beavers, the lumberjacks of the wild, are a large nocturnal, semi-aquatic rodent. The North American beaver is native to the continent and is featured as a prominent national symbol for Canada. The Eurasian beaver spans a much greater range, living within Great Britain, Spain, Central Europe, Scandinavia, China and Mongolia.
The beaver is the 2nd largest rodent in the world behind the South American capybara. The North American beaver weighs on average approximately 20kg.  Beavers can be 74-90cm long with the tail adding an extra 20-35cm of length. 
Beavers are well adapted to their semi-aquatic lifestyle. The iconic, paddle-shaped tail allows for higher maneuverability in the water and is used to loudly slap the surface of the water to intimidate predators as well as warn other beavers in the area of danger. Their hind-feet are webbed, acting as flippers, while their agile front feet are more suitable for digging and holding objects. They also have a third, translucent eyelid called a nictitating membrane. This allows them to see effectively underwater.
The beaver is renowned for its ability to create dams using the surrounding trees. Beaver’s teeth are extremely hard, their four incisors have an iron acid-resistant enamel unlike any other mammal. This in combination with the rapid speed they grow enables them to chew down tree’s much larger than themselves.
The beaver dam’s main function is to protect themselves from predators, as well as create water deep enough to stop it from freezing in the winter. Water is crucial for a beaver fleeing from a predator, as their superior movement and ability to swim underwater allows them to easily escape. The dams also double as a food source, since beavers eat bark, twigs and leaves. As mostly nocturnal animals, they build these dams at night, using a variety of mud, stone and timber.
Once a pond has been formed by the dams, the beavers will create a home inside the pond called a lodge. These are mostly made of branches and mud, with the mud being applied to the outside of the branches just before winter. This mud will freeze and become as hard as brick, making it nearly impossible for predators to penetrate the lodge. The lodge’s only entrances are underwater, so predators must break apart the lodge from above.
Beaver populations have been steadily declining in recent centuries, once the North American beaver population was predicted to be above 60 million. Now it is closer to 10 million. This is due to the extensive hunting for their fur, which was crucial to the North American fur trade in the 17th century. Their European and Asian counterpart fared much worse, with the species nearly being hunted to extinction. Efforts were successful to reintroduce the species and now they are no longer considered a threatened species.
Surprisingly, beavers may be beneficial to some countries facing increased flooding from climate change. Trials in Britain have shown that beavers provide enormous benefits to surrounding areas, protecting nearby lands from flooding and preventing damaging sediment from farmland spreading to surrounding wildlife. The beavers themselves aren’t overtly affected by the changing conditions climate change brings, and are acting as a reversing agent to some of the more negative impacts.
 Müller-Schwarze, D., & Schulte, B. A. (1999). Behavioral and ecological characteristics of a “climax” population of beaver (Castor canadensis). In Beaver protection, management, and utilization in Europe and North America (pp. 161–177). Springer US.