Staying Sharp By "Self Sharpening"

Beaver Teeth That Are Literally Made of Steel
If you’ve ever looked at the incisors of beavers, you might have thought they were good candidates for teeth whitening. Their teeth usually look orange or brown, not bright white like human teeth. If you’re wondering why beavers teeth are orange, it isn’t staining from their environment, it’s actual iron in their tooth enamel! As you might suspect, that iron makes their teeth stronger and better able to cut through wood.

But here’s what’s strange about these beaver incisors: they only have enamel on the front of their teeth. The back surfaces of their incisors are exposed to dentin. This might seem like a disadvantage, but it actually helps keep the beaver teeth sharp. Because the dentin at the back wears away faster, it creates a sloping angle on the teeth, a perpetual edge.

Beaver teeth are so good at cutting wood that they have used tools by early humans. The oldest known wooden statue is believed to have been carved in part with tools made from beaver jaws!

Your Teeth Are Meant for Chewing Food