I had never seen a black squirrel before I came to Western. The squirrels I had seen in my home town were gray or brownish-gray, darting across the street and running up telephone poles. I was a lonely freshman when I saw my first black squirrel frolicking in the grass near the entrance to Wilson Library.

I developed the hypothesis that these were Canadian squirrels venturing south of the border. But how could this be? Squirrels have no concept of national boundaries that I know of. My quest for answers took me to the biology department.

“All the squirrels you see in town are the eastern grey squirrel, or Sciurus carolinensis,” associate professor of biology Roger Anderson said.

As the name implies, the eastern grey squirrel is not from around here. According to Anderson, the eastern grey squirrel was introduced to the Western United States by humans. This is the type of squirrel you typically see roaming the suburbs here in Western Washington.

There's also Sciurus griseus, the western grey squirrel. These squirrels are indigenous to the western United States. They don't live this far north, but are a little more common farther south and east of the Cascades. Western grey squirrels mostly live in the wild, and have not taken to the suburban habitat as easily as the eastern grey squirrels, Anderson said.

Eastern grey squirrels look grey, but their hairs are actually banded with different colors. As the hair grows, pigment cells develop melanin in the hair. There are two kinds of melanin in the hair of squirrels: eumelanin and pheomelanin. Eumelanin gives the hair a black color, and pheomelanin gives it a red or yellow color. The combination of these two types of melanin looks grey, Anderson said.

However, there are variations in color between individual squirrels.

“The genetics to it are surprisingly complex,” Anderson said.

Some eastern grey squirrels have more pheomelanin, and therefore look more brownish or reddish. Others have more eumelanin, and thus appear black. Neither type of coloration is very uncommon. In fact, black, grey, and brown squirrels can all appear together in the same litter, Anderson said.

But if black squirrels aren't uncommon, why had I never seen one before I left for college? And why have I only seen them here on campus?

As it turns out, it's no coincidence that there seem to be more black squirrels here at Western. Black squirrels are actually more common farther north, Anderson said. This may be because their black pigment helps them pick up more sunlight and stay warmer.

Also, the black squirrel has established itself more on college campuses and in suburban communities. It's possible that black squirrels are easier to spot in the woods than their grey and brown counterparts, and that this makes them an easier target for predators, Anderson said.

Other college campuses have become safe havens for black squirrels. Students at Kent State University in Ohio and Houghton College in New York have started Facebook groups in honor of black squirrels. There are at least three black squirrel Facebook groups started by Western students.

Like the sculpture outside Wilson Library, “The Man Who Used to Hunt Cougars for Bounty,” the black squirrel is nearly an unofficial mascot to Western students. Some like to think of them as ninja squirrels. Others suspect they may be omens of good or bad luck. Whatever their supernatural qualities, remember to show goodwill and hospitality to our bushy-tailed friends.