by Greg Mayer
Squirrels are, of course, perennial favorites here at WEIT, being known as honorary cats. They also present a number of interesting phenomena of within and among population variation in easily observable traits like pelage color. Because these variations are often known even to casual observers, I often use squirrels as examples when explaining what species are. In eastern North America, gray squirrels, fox squirrels, ground squirrels, chipmunks, and woodchucks provide many informative examples of the differences within and among species.
We’ve had occasion to comment here on albino, parti-colored and black squirrels, all of which are gray squirrels (Sciurus carolinensis). I was thus intrigued when my Toronto correspondent sent along a photo, taken in Port Huron, Michigan, of a black squirrel with a brownish tail.
The body looks like a typical melanic squirrel– black, although when seen up close, they often have some reddish/brownish in them– but the tail is brown! Black is usually the result of the pigment eumelanin, while browns and reds often are due to the presence of phaeomelanin, so melanics can have both pigments present. In the Port Huron squirrel, the tail (although not the underside of the base, which is black) perhaps has only phaeomelanin. There were “tons” of regular melanics in Port Huron, but just one with the lighter tail.
I have seen melanics and albinos in the wild, but I had never seen– in the wild, in a museum, or just in a photo– a melanic with a brown tail. I consulted a colleague with a great deal of field experience in Wisconsin, especially northern Wisconsin, and he too had not seen them. I was surprised to learn after consulting a standard reference (Fiona Reid‘s volume on mammals in the Peterson Field Guide series– highly recommended) that such squirrels are in fact well known, especially from further north in the range of the squirrel.
My Toronto correspondent also sends a photo of a black squirrel from Toronto itself. Black squirrels are quite common in Ontario: my correspondent writes, “[I]n Toronto, I feel as if I see a black squirrel every time I turn around!” The interest of the pictured squirrel is that it seems to have light spots on the forehead and back; she said it looked “spotted”.
You can see the white spot on the forehead; there’s another, just barely visible in this photo, in the middle of the back. I have never seen this pattern either. I did find though, through a link provided by Jerry, the opposite pattern: a photo of a white squirrel with darker spots on forehead and mid-back from Brevard, North Carolina, where white (and mostly white) squirrels are common.
The white morph of Grey Squirrels seems to appear here and there. For instance there are a few populations around my area (North Florida) with high frequencies of leucitic (definitely not true albinos) individuals like the squirrel from N.C. pictured above.
And as for other tree squirrels, Fox Squirrels in Florida seem to show more variation than I’ve seen elsewhere. The Sherman’s Fox Squirrel has a handsome coat with a mostly grey body and a dark facial mask.
I’ve seen photos of melanistic grays with red tails, all from the Great Lakes region.
Yes, here in Michigan I see a lot of those in my yard! And other weird coat color combinations as well. The variety has increased over the 30 years we’ve lived here.
http://www.wunderground.com/wximage/RenegadeMama/1
Very nice photos at the link; the red-tailed black squirrel (or squirrels– not sure if it’s the same in both photos) pictured is from Michigan.
GCM
LOL, as I was just saying above… 😀
There is a black squirrel with a blonde tail in Grange Park,Toronto (1 block north of City TV/Much Music HQ). We also had an albino squirrel in Trinity-Bellwoods Park which unfortunately died last year (down the street from the park there is a road “White Squirrel Way” that leads into the CAMH facility. We also have red squirrels in High Park and a few of the other forest areas of the city. The majority of squirrels are black and grey and a lot have different colour variations. Feel free to use my pictures.
Jason
I’m in the Raleigh, NC area, far from the mountains of Brevard. Geographically at the eastern edge of the Piedmont (the Inner Coastal Plain starts at a fall line just east of Raleigh).
We have many Eastern gray squirrels, Sciurus carolinensis here, but sadly, in my many years in the area I have never seen a melanistic or albino individual. 🙁
I wonder if mountain populations tend to be more geographically isolated allowing the color mutations to be more prevalent.
Of course, if that hypothesis is correct The forest cover in this area was very fragmented by heavy agriculture leaving us with generally young pine (<50 yrs)forests. Perhaps the squirrel populations can travel across such landscapes more easily than in mountain forests?
Any thoughts? Anyone in my area know about local populations with color mutations? I'd love to see some.
Here in the UK we have the ubiquitous Grey Squirrel, and all I see out of my rear window are Greys, the Native Red Squirrel is beginning to make a comeback thankfully.It was decimated by the introduction of the Grey Squirrel but in its strongholds in the North of the Country it’s recovering.
I am personally convinced that the UK grey squirrels are getting redder. I seem to be seeing more “greys” with a reddish tinge to their fur, especially as compared with what I remember from childhood. I suspect that it may be an adaptation to the colours of UK foilage…?
I’ve thought my Grays here in Michigan have been getting redder as well, though.
The redcoats are coming…?
Ha ha.
We’ve had a dark grey one with a totally “bleached” red tail here for a couple of years now ( outside Toronto). It looks completely healthy except for the weird tail.
The white marking on the forehead is often called a ‘blaze’, and is seen in pretty much all mammals including humans. I do not know about the general rule of genetics surrounding this marking.
Diana had it on some of her bunnies.
I often see black squirrels with brown bums & tail.
I suspect that the melanic is dominate because we had only the greys here for a long time. Then we introduced 2 black squirrels from town and now more than half are black.
Yes, when I was a grad student in NY, I remember hearing about a rare populations of melanistics some place in New England or SE Canada. Now they’re ubiquitous.
I live in Ontario, and black squirrels have made nests in the two maple trees in my front yard AND (for the first time), atop the large trellis in my backyard.
Sub
Spent a summer in Brevard (catchin’ bears); they are very proud of their white squirrels, and have an annual festival. Apparently the original pair escaped from a circus in 1949.
According to local lore, the circus acquired them from their original home in “islands off Hawaii”, or maybe China. A Florida source seems much more likely!
A paper about their (cat-driven?) evolution:
How are white squirrels able to survive in a forest? J.C. Hodge
Blue Ridge Community College, 100 College Dr., Flat Rock, NC, 28731-1690
Abstract
The white squirrels’ (Sciurus carolinensis) causes of success in a preditory environment and causes of the apparent population equilibrium with gray squirrels are mysteries. White squirrels of Brevard, NC are thought to be a color variant of the Eastern gray squirrels. White and gray squirrels were observed from 2001 to May 2010. The squirrel population in the observation area has changed from predominantly gray to predominantly white. The observations suggest white squirrels have many physical and cultural characteristics that differ from gray squirrels. These characteristics favor white squirrels over gray in a substantial feral and stray cat (Felis catus) predation and human environment. That Brevard white squirrels may be at an evolutionary branching point is suggested.
Here in Muncie, Indiana, just a few weeks ago, my wife and I were driving through a neighborhood adjacent to the Ball State University campus. As I glanced toward the yard of a house we were passing, I saw a squirrel, gray or black, with what appeared to a blond tail. When I remarked to my wife about it, she gave me one of those looks that means, “Sure you did.” Although we have driven through that neighborhood many times since then, I have not seen the squirrel again, but the photo in this post looks very much like what I saw. Maybe now she will believe me.
“Ours” certainly has a blonde tail.
My husband and I recently drove through Wyoming where I read a local newspaper article about albino prairie dogs. Today, I read one article about albino prairie dogs on the Wind River reservation in Wyoming and another about albino prairie dogs in North Dakota. There was reference to a town protecting albino prairie dogs that proliferate and do well in town, whereas those living outside of town do less well due to predators.