Teeth:
* Large, ever-growing incisors: Their front teeth, called incisors, are massive and continuously grow throughout their life. This ensures they always have sharp teeth for gnawing.
* Hard enamel on the front: The front of the incisors is coated with extremely hard enamel, which is much harder than the back of the tooth. This creates a chisel-like edge, ideal for cutting wood.
* Soft dentin on the back: The back of the incisors is made of softer dentin. This allows the teeth to self-sharpen as the beaver chews. As the harder enamel wears down, the softer dentin is worn away faster, creating a sharp cutting edge.
Muscles:
* Powerful jaw muscles: Beavers have incredibly strong jaw muscles that allow them to exert enormous force when chewing. These muscles are responsible for the grinding power needed to break through tough wood.
Other adaptations:
* Open-ended jaw: The lower jaw of a beaver can rotate forward and backward, giving them a greater biting range and allowing them to use their teeth like a saw.
* Unique biting technique: Beavers don't chew in a typical back-and-forth motion. They gnaw in a sideways motion, using their incisors like a pair of powerful chisels.
These adaptations allow beavers to fell trees up to a foot in diameter, creating logs for their dams, lodges, and food storage. Their ability to continuously grow and sharpen their teeth ensures that they can keep chewing through wood throughout their lives.