A few days ago, a person somewhere on social media had mentioned seeing a ball in a tree. I almost knew what the person was talking about without reading the rest of the story.

A few years ago, during winter, I saw a ball-shaped object in a far-off hemlock tree. It was about the size and shape of a large hornet nest. As I got closer, however, the hornet nest became a porcupine up in a tree.

That porcupine was likely resting; it was pretty still. Porcupines are primarily nocturnal, though they can be seen moving around during the day. These animals either rest in their dens or up in trees, as this one appeared to be doing.

Another reason that porcupines are frequently found in trees is that they feed on green twigs and shoots. Sometimes they climb way out on branches to get at shoots. They will also eat the bark of some trees. This is mostly a winter activity; when spring arrives, they have a greater choice of vegetation to feed on.

A porcupine is well known for its quills; there are up to 30,000 of them on its body. A porcupine cannot “throw” its quills, instead, the would-be predator attacks the porcupine, and quills, each equipped with microscopic barbs, embed themselves in the predator’s body.

A porcupine will twitch some muscles in its back, and the quills will stand on end and detach if the target is found. Porcupines also swing their tails towards a predator and make contact if close enough.

Sometimes, a porcupine’s victim can be a curious dog; if you choose not to go to the vet, use good pliers and pull the quills straight out. Do not cut them or break them off. If any are broken off at skin level, it’s best to get professional help.

Porcupines can weigh up to 30 pounds and are the second-biggest rodent in the region; only the beaver is larger. They are easily spotted and may try to climb a tree if you get too close.

Breeding occurs through November; that’s when males search for females, and as they try to cross the road, many of these males get hit by vehicles.

Females typically have a single young—a kit—seven months after breeding. The young are born with soft quills, which harden a few hours after birth.