Nov 08 2010

This is a Gray Squirrel

Published by at 8:02 am under Mammals,Schenley Park


Yes, really.

Black squirrels are not a new species, they’re just a common melanistic color phase of the eastern gray squirrel (Sciurus carolinensis).

“Melanistic” comes from the Greek word for black, melanos, and is caused by melanin, the brown or black pigment that gives hair, skin and eyes a dark color.  Melanin can be inherited for a permanent dark color as in this squirrel, or it can be produced in greater quantities during tanning or in some diseases.

Melanism can confer a biological advantage when it provides better camouflage.  There’s even an effect called “industrial melanism” in which the majority of a species living in a dirty, industrial zone are darker than those who live in a cleaner environment.  This was famously documented among peppered moths in Britian during the sooty, late-1800s.

Who knows why Pittsburgh has black squirrels (we haven’t been sooty for half a century) but if you want to see them come on over to the area of Schenley Park that borders — you guessed it — Squirrel Hill.

(photo by D. Gordon E. Roberston from Wikimedia Commons.  Click on the photo to see the original)

7 responses so far

7 Responses to “This is a Gray Squirrel”

  1. Tomon 08 Nov 2010 at 5:51 pm

    There are many black squirrels in the New Philadelphia/Canton area of Ohio. First noticed them on a visit to friends about 10 years ago and still interests me every time I viist.

  2. faith cornellon 08 Nov 2010 at 6:22 pm

    Never saw one when I lived in Beaver County & have never seen one yet here in Bridgeville nor at parks where I walk. So beautiful & different. Thanks for the great picture.

  3. John Englishon 08 Nov 2010 at 7:36 pm

    I recall that for at least 40 years there has been a colony of melanistic squirrels around Aylesboro and Northumberland Avenues near Schenley. Have recently seen some “migrants?” over around Abbott and Cromwell near Frick. They are a striking animal to see.

  4. Peteron 08 Nov 2010 at 7:41 pm

    I love squirrels. I’m a nut! But never looked into them enough to know they were just a variation of the same species. Thanks for sharing. I think I must see some of the same individuals you do as I usually catch them near the footbridge where the Panther Hollow trail comes out by the light at Greenfield Ave & the boulevard. I usually stop and watch them a while. Always thought they looked smaller, but I must have been forcing my impression of them as a separate species onto them. There are so many more of the brown coloration there…I hope the red-tails continue to chase them and don’t get after these guys.

  5. bruce burnfieldon 10 Nov 2010 at 7:48 pm

    back in the 70′s I used to visit friends attending Kent State University, where black squirrels were everywhere.
    we were always told someone imported the black rodents in fom Canada.
    Have you ever heard this?

  6. Kate St. Johnon 10 Nov 2010 at 9:57 pm

    I have not heard the “imported” story. Gray squirrels are the same species in both Canada and the U.S. so it would be hard to tell if someone moved them around.

    I do know that North American gray squirrels were imported into Britian. I hope that experiment did not turn out as badly as our experience with imported European starlings (which have taken over).

  7. Mary Ann Pikeon 11 Nov 2010 at 9:21 am

    Oddly enough, although I haven’t seen one for years, I saw a black squirrel on my drive into work today! Interesting that this happened not long after your post. I agree with the person who said they look smaller than other squirrels, but maybe I just see several species of different sizes around my feeders and they are members of one of the smaller species that lives around here.

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