Why Do Beavers Have Orange Teeth?

Updated: Apr 8

Beavers chomp through trees with bright orange front teeth. Are beavers just forgetting to brush? Your dentist might not be happy to see a mouth full of orange, but beavers need their bright choppers.

(Photo via Shutterstock)

Always growing


Like all rodents, beavers have front teeth, called incisors, that never stop growing. To keep them in check, rodents must constantly gnaw on hard surfaces like wood. Beavers’ incisors can grow up to 4 feet per year. That is the size of most adult beavers’ bodies without the tail! Can you imagine your teeth growing all the way down to your toes?

 

Words to know

Cambium: Plant tissue found under the bark in trees.

Dentin: Hard, dense bony tissue in the teeth.

Enamel: The hard outer covering on teeth.

Gorge: To eat a large amount.

Incisors: A narrow-edged tooth at the front of the mouth that is adapted for cutting.

 

This seems like a dental superpower, but it comes with a downside. Crooked teeth that can’t get shaved down will continue to grow and grow and grow, getting in the way of their mouths. If it gets too out of hand, they can starve because they can’t eat.

Metal mouth


The reason their ever-growing incisors are yellow or orange or brown is because their tooth enamel has iron in it. Iron is strong stuff and makes their enamel super hard. It also makes their teeth resistant to acid. It turns out iron is better at preventing against cavities than the fluoride you get in the dentist office.

Can you see the enamel? How about the dentin? (Photo via Shutterstock)

We have the hard enamel coating all over our teeth. Beavers only have it on the front of their incisors. The backs of their teeth are made from dentin, which we have under our enamel. Dentin is harder than bone, but softer than enamel. This means dentin wears away faster, creating a sloping angle that looks like a chisel. The very sharp edge helps with chewing wood.

The perfect tool


Beavers’ incisors are so incredibly sharp that people made tools out of them! The world’s oldest wooden statues were carved about 11,000 years ago. Found in the peat bogs of Russia’s Ural Mountains, they are three times older than the pyramids of Egypt. Ancient people carved the faces using beaver jaws with the teeth still intact.

Teeth saws


One of the main reasons beavers have such strong teeth is so they can eat. They gorge away on bark and cambium, the softer tissue just under the bark. Not just any tree will do. Their favorites are willow, maple, poplar, beech, birch and aspen. They also go for roots, buds, leaves, vines and twigs. As strict vegetarians, beavers will also treat themselves to softer meals like apples, grasses, water lilies, clover, cattails and watercress when they are around.

When not chopping down trees to eat, they use the lumber to build dams and lodges. Domed lodges are where they live, and dams engineer deep ponds that protect their homes from coyotes and other predators.

It’s quite convenient that they can snack while they build! Either way, one beaver can chop down 200 trees a year!

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