Asides from being the second-largest rodent in the world, the physical biology of the beaver make it one of the most unique looking semi-aquatic mammals. As beavers are nocturnal animals that typically avoid humans, it’s a rare occurrence to happen upon them.
North American beavers have thick, stocky bodies with a brown-black coat of fur and a broad, flat, scaly tail that acts like a rudder to propel them through the water. Due to their stocky frame, beavers can conserve heat and remain active even in the wintertime. Their large orange teeth grow continuously throughout their lifetime, requiring them to gnaw on trees to keep them properly filed down.
These long, visible incisors are self-sharpening and if grown too long, they prevent a beaver’s mouth from closing enough for its grinding molars to meet, which leads to starvation.
Beavers are semi-aquatic, moving between water and terrestrial environments. They have small, dexterous front feet that are well adapted to working on the land. They have five digits and are able to grasp and hold sticks with well-developed digging claws.
Their hind feet are larger and webbed to make swimming easy. These hind feet have a “preening toe” that has a double toenail intended for grooming and preventing mattes. This also helps maintain its waterproofing and insulating properties.
Beavers move quite awkwardly on land, making them vulnerable to predators. Having said that, beavers can swim up to 10 kilometers per hour, while their large lungs allow them to stay submerged for up to 15 minutes.
Their whiskers help beavers detect objects around their face and head, which helps them find narrow passageways in dark water. Their eyes have a thin, transparent layer called a nictitating membrane, acting as a shield to allow beavers to see underwater and protect the eyes. However, their sight is only good for short distances and at a close range.
As for their ears, they’re external, small and rounded, and contain valves that close while submerged underwater.
Beaver’s tails can be quite unique depending on their family and vary from being short and broad to long and narrow. Tails are effectively hairless and covered in black scales. This tail serves many practical functions, acting as a propeller, a brace when sawing down trees, communication tools to ward off predators, and energy storage units, increasing their fat supply for the winter. There is a sharp separation between the beaver’s fur and scales.
The largest rodents in North America, beavers are the second-largest in the world. The largest in the world is South America’s capybaras. Beavers can weigh between 35 and 65 lbs (or 16-30 kilograms).
If you ever get to see a beaver in person, make sure to keep a respectful distance and appreciate these amazing mammals from afar. Beavers are typically afraid of humans, so don’t be too surprised if they scurry away if you happen upon one.
Maybe if you’re lucky, you can snap a picture of a member of this elusive keystone species.