Newsgroups: sci.bio
Path: utzoo!snell
From: snell@utzoo.uucp (snell)
Subject: Re: Black Squirrels
Message-ID: <1988Feb4.094730.8182@utzoo.uucp>
Organization: U of Toronto Zoology
Date: Thu, 4-Feb-88 09:47:25 EST

In article  <4400@pucc.Princeton.EDU>


>>Where I went to high school in Indiana, there are two towns separated by maybe
>>5 miles.  In both of these towns there are "Black Squirrels".  They are
>>smaller than normal squirrels and are not found in any of the surronding
>>areas of Indiana.  When I talked to some of my friends in the area they
>>said that the squirrels are descendants of squirrels imported a long time ago.

Though possible, there is no reason to believe this.  The black squirrels
are almost certainly one of the dark (melanistic) morphs of the common
Grey Squirrel _Sciurus carolinensis_.  The larger grey ones are almost
certainly Fox Squirrels _Sciurus niger_.   Though _S. carolinensis_ is
grey or dark-brown, or black, within any particular geographic locality
there is NO difference in their size.  (Grey Squirrels vary considerably
in size over their geographic range, with the ones in the Florida Keys
being very tiny indeed compared to the northern variety near Winnipeg--
all are the same species though.)  The melanistic morphs become
exceedingly rare to non-existent south of a general latitude near 
southern Pennsylvannia.  Further north, as at Toronto, the melanistic
forms are just as common as the grey morph (and there are no Fox Squirrels
here, either).

> 
>Princeton, in New Jersey, also has a black squirrel population,
>known to have been imported from Canada by the wife of one of the
>University presidents.  She kept a menagerie, and at some point
>many of the animals were released.  

This may or may not be true, but there is no reason to believe that
this hypothetical event was in anyway responsible for introducing
black morph Grey Squirrels in this region.  The two dark morphs
and the greys have been present throughout these northern regions
since at least the time of Audubon (early 1800's).

>The squirrels here may have
>come from Brittish Columbia, 

If black-morph Grey Squirrels came from British Columbia, which
I certainly doubt, they themselves were derived from a founded
population.  The species was introduced in Vancouver, and is 
doing nicely in Stanley Park.  The natural range just barely
makes it into Saskatchewan, extending west from Maine and New Brunswick.

>and I believe these pocket
>populations have been investigated in the scientific literature
>due to the current interest in modes of speciation.

This is also not true, though I would love to have a reference to such
a published study on the Grey Squirrel _Sciurus carolinensis_.
> 
>>I would like to find out where they came from.  What kind of resources are
>>there to help me find out what part of the world the squirrels are native?

They are endemic to the area you have found them in.

>If you wish, I will try to find some more information about the
>Princeton squirrels on campus.  Try looking in some of the annual
>biological citation indices under squirrels, and crossreference
>whatever you find with words like "black", "isolated", etc.

Whatever you do, do not do a computer search using the word "black."
If you have to pay a few cents per citation, you will have a bill
in the many many thousands of dollars, and virtually none of it
will relate to squirrels.
-- 
Name:   Richard Snell
Mail:   Dept. Zoology, Univ. Toronto
        Toronto, Ontario, Canada    M5S 1A1
UUCP:   {allegra,decvax,ihnp4,linus,pyramid,yetti,utai}!utzoo!snell