Beavers and porcupines have much in common. These interesting species are large rodents that live in Pennsylvania’s forests, as well as in woods across much of North America.

Both have large, orange teeth they use to consume tree bark, twigs, and other tough vegetation. Both are fairly common in woodlands these days.

And, as with all rodents, their teeth grow throughout their lives, which is essential because of the wear those teeth sustain while gnawing bark and twigs.

But beavers and porcupines have differences, too, which make them distinct species. Beavers live at ponds they create on woodland streams by damming those waterways.

Porkies mostly dwell in tall trees in the woods. These different niches reduce competition for living space and food between these woodland rodents.

Beavers have luxurious, dark-brown fur and weigh up to 50 pounds. Each beaver has a 10-inch-long, 6-inch-wide, flattened, hairless tail that is covered with scales.

It uses its tail for steering while swimming with its back legs, storing fat, patting down mud on log-and-twig dams and lodges, and slapping water surfaces to warn of danger.

And its nostrils, eyes, and ears are set near the top of its head so it can breathe while smelling, watching, and listening for danger while the rest of its body is out of sight under water.

Beavers chew down young, soft trees — including aspens, birches, willows, and certain maples — with their strong teeth. They eat the twigs, buds, and bark from those trees and use the logs and branches to make dams and lodges.

Dams back up streams and form ponds. Beavers build secure homes of logs and limbs in the ponds, with underwater entrances to their homes. There, each pair lives and raises young.

Porcupines grow to be 3 feet long and up to 20 pounds. They are solitary, except when mating or raising a single young each year. Each porky dens in a tree cavity or a hole in the ground.

Porcupines are famous for their white-tipped, black quills that are modified hairs used to protect these creatures. The tip of each quill is barbed, which allows it to be better imbedded in an attacker.

When threatened, each porcupine turns its back to the aggressor, lowers its head, raises the quills on its body and tail, and swings its tail from side to side. Few critters try to get through that defense!

Porcupines are also famous for their craving of salt and other minerals. They consume shed deer antlers for calcium and other minerals. And they chew on axe handles and other wooden tools left in the woods because of the salt on the wood from sweaty human hands.

Beavers and porcupines are big, interesting rodents that are part of many woods in Pennsylvania. Though related, they follow different lifestyles; this allows them to live in the same forests with little competition for shelter and food.


Clyde McMillan-Gamber is a retired Lancaster County Parks naturalist.

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