Walk through City Hall Park in Lower Manhattan and you’ll notice several things.
There are the people in suits who are usually in a hurry. There are tourists — lots of them. As it is quite a lovely outdoor space, there are a number of trees. And then there are squirrels. More squirrels than seems natural.
Some of those squirrels may seem unusual. They’re not the typical, boring, grayish-brown rodents we all see hopping from branch to branch outside our windows. They’re jet-black with maybe a tinge of red. Good-looking squirrels, really.
They’re not a different species, though they might look that way. The black squirrels are just standard, run-of-the-mill Eastern Grays with a relatively rare genetic trait called melanism that makes them extra dark. And there are a lot of them in City Hall Park.
It’s not clear exactly how rare the trait is, but the melanistic variety of Sciuris carolinensis typically don’t appear in large concentrations. Except, that is, in isolated parks like this one. It’s a result of what urban ranger Sunny Corrao calls the “island effect.”
“Because the park is surrounded by this very heavy urban area, the squirrels are staying within the park,” says Corrao, who works for the New York City Department of Parks and Recreation. “So in a sense, it’s like an island.”
In a place like New York City, where patches of prime habitat like City Hall Park are isolated, Galapagos-style, by concrete and cars and dogs in tiny sweaters, squirrels and other wildlife tend to stay put. The interbreeding produces more of the black squirrels, hence our urban flocks.
But there are other, more awesome reasons why melanistic squirrels might be more common in an urban environment. While they’re comparatively rare outside major cities, some biologists believe that black squirrels may have been the norm several centuries ago, before large-scale deforestation. Today’s woodlands are much less shady than the virgin stands of old-growth, high-canopy forest that used to cover the Northeast. And in environments with more sunlight, “squirrel gray” might offer better camouflage. But cities, with their tall buildings, may mimic the darker environs of the early continent. According to Corrao, it might also be that cities simply have fewer predators, so camouflage isn’t as important anyway.
“There’s something in that environment that makes it so being a darker color isn’t necessarily a negative trait,” she says. According to Corrao, parks in the outer boroughs seem to have lower concentrations of squirrels with the unusual color, but the city doesn’t track the population, she notes.
There are populations of melanistic squirrels in other parts of the city, too. There are the famous ones near the Stuyvesant Town developments on the Lower East Side. And there’s a cluster on Long Island that has been studied by middle school students. There are also cinnamon-colored squirrels and the occasional white one.
And as many will undoubtedly point out — especially the Canadians lurking here among us — there are some places where the black squirrels are quite common. Canada is apparently crawling with presumably very polite melanistic squirrels. Some data suggests that darker fur might offer an evolutionary advantage, holding heat as much as 18 percent more efficiently, so it would make sense that they’d be more common in colder climates. Some of the city-dwelling Canadian squirrels are also famous, like the ones in Queen’s Park in Toronto.
New Yorkers seem to have been fascinated by black squirrels for years. They’ve been making the paper since at least 1902, when a woman was caught trying to smuggle a baby black squirrel out of Central Park, only to be caught by an attendant. As the Times reported way back then, “regretfully she pulled her hand out from under her cape, [Ed: her cape!] and snugly nestled in it was a little squirrel, black as coal.”
A man identified only as Arsenal Director Smith ordered that the baby squirrel be added to the zoo in Central Park. Smith also wanted the squirrel treated like royalty, declaring that it “should be well taken care of; that it should be fed on nuts cracked for it, and be given plenty of milk in the hope of keeping it alive for the purpose of adding it to the menagerie family.”
“They are very rare, these black squirrels,” Smith told the paper. “I never saw one in my life before, and I have seen a good many curious animals. It is a freak of nature.”
After the Times wrote about the mysterious caped woman’s attempt at squirrel theft, one reader — a Canadian — wrote in to complain about the paper’s ignorance. The letter is downright un-Canadian in its rage.
They take their squirrels seriously up there.