|Close-up of incisors. Enamel is orange, dentin is white. Note the wedge profile.|
This wedge profile allows the beaver to cut wood quite easily with its teeth. It uses its upper incisors as a fulcrum, holding its head in place as it chews. Its lower incisors bite into the wood, shaving off strips.
|Strips removed from a tree trunk|
With these teeth the beaver is able to fell and buck (cut into lengths) quite large trees like this Red Maple (Acer rubrum).
|The tape measure is about 3.5 inches long. This tree measured over 14 inches in diameter. Note the chewed log in the background.|
|A riverbank food cache|
|River floodplain after beaver logging activities.|
While the modern North American Beaver is a medium sized herbivore, reaching lengths of up to 4 foot (including an 8 to 14 inch tail) and weights of 50 to 60 (occasionally 100) pounds, during the Pleistocene the modern beaver was joined in Michigan by an enormous cousin the Giant Beaver (Castoroides ohioensis). The Giant Beaver could reach lengths of 6 to 8 feet and a weight of up to 600 pounds - although most probably weighed less than 300 pounds. This behemoth probably did not cut down large trees, but rather ate aquatic plants much like a modern Muskrat.
|A replica Giant Beaver skull (left) and a modern North American Beaver skull (right)|
The modern beaver was once hunted and trapped almost to extinction across much of North America for its fur. A fashion for beaver felt hats drove this pursuit from the 1600s through the 1830s. The beaver may have been driven to extinction if fashion had not changed; in the 1830s the fashion shifted from felt hats to silk hats. Today, the population of beaver has rebounded across much of its historic range and continues to expand.