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Melanistic Gray Squirrel, Sciurus carolinensis, Observed in the
Piedmont Region of North Georgia
Gary W. Barrett1,* and Terry L. Barrett1
Abstract - A melanistic morph of Sciurus carolinensis Gmelin (Eastern Gray Squirrel or Gray
Squirrel) was observed on 17 and 27 September 2008 in the Georgia Piedmont, Athens-Clarke
County, GA. This is a rare observation because we have found no reports of Gray Squirrel melanism
located south of Virginia in the southeastern United States.
Melanism in Sciurus carolinensis Gmelin has long been of interest to biologists and
ecologists. For example, Nelson (1918:445) described and illustrated the black phase
(morph) of the Gray Squirrel in National Geographic Magazine. He noted that litters are
found to contain black young in some parts of America, but no additional information was
provided. Shorten (1945) reported on variation found in melanistic Gray Squirrels, such as
melanistic individuals with brown under parts, or with hairs on the back tipped with brown.
Although the range of S. carolinensis covers the deciduous forest biome of the eastern United
States from Nova Scotia to Florida, west to southwestern Saskatchewan, a large portion
of North Dakota, and eastern Nebraska, Kansas, Oklahoma, and Texas (Whitaker and Hamilton
1998), melanistic individuals are only common in the northern part of its range, where
they are frequently described as black above and pale brown below.
Melanism in the Gray Squirrel is found primarily in urban populations and near the
northern limit of the species range. Steele and Koprowski (2001) report that melanistic
Gray Squirrels are common in southern Ontario, Canada. Thorington and Ferrell (2006)
note that black morphs are common in the Washington, DC area and as far south as
Prince William County, VA. Gustafson and VanDruff (1990) describe behavior of black
morphs of S. carolinensis found primarily in urban populations, such as Syracuse, NY.
They note that among exurban populations (i.e., in districts outside a city), the black
morph is abundant only in Canada and in Northern Michigan. In summary, distribution of
S. carolinensis color morphs has perplexed biologists for decades (Banfield 1974, Creed
and Sharp 1958, Schorger 1949).
On 17 September 2008, we observed an adult melanistic S. carolinensis at the edge of
a hardwood forest located in Athens-Clarke County, GA (33°57'19"N, 83°22'59"W). The
melanistic Gray Squirrel returned to the same site on 27 September 2008, but was not
observed again, although 10 to 15 Gray Squirrels come daily to a ground-feeding station
at this site. This is the first report of a melanistic Gray Squirrel in the Georgia Piedmont.
The individual that we observed had a completely black dorsal area, white hairs around
its nostrils, and a few gray hairs on its ventral under parts. The forest site of observation
is located on private property and dominated by Quercus velutina Lam. (Black Oak),
Q. falcata Michx. (Southern Red Oak), Q. alba L. (White Oak), Fagus granifolia Ehrh.
(American Beech), Liquididambar styraciflua L. (Sweet Gum), and Liriodendron tulipifera
The existence of melanistic individuals in wild Gray Squirrel populations is seldom
well explained. Introduction of one or more melanistic squirrels is a possible explanation
regarding our observation. We have no evidence, however, that introduction of melanistic
Gray Squirrels has occurred in the Georgia Piedmont.
1Eugene P. Odum School of Ecology, University of Georgia, Athens, GA 30602. *Corresponding
author - firstname.lastname@example.org.
Notes of the Southeastern Nat u ral ist, Issue 10/1, 2011
190 Southeastern Naturalist Vol. 10, No. 1
From an evolutionary perspective, winter temperatures of extreme cold (-10°C) in the
northern United States and southern Ontario, Canada provide the melanistic Gray Squirrel
with an energetic advantage, while in summer there is no advantage or disadvantage
(Ducharme et al. 1989, Innes and Lavigne 1979). We doubt that black morphs have any
advantage in the southeastern United States. It has been suggested that melanistic Sciurus
niger Gmelin (Fox Squirrel) in the southeastern United States are related to historical
frequency of forest fires (Kiltie 1989, 1992). The area of our observation has not been
burned for decades. Because none of these possible explanations seems plausible, we
suggest that our observed black morph occurred naturally within an abundant wild population
of Gray Squirrels observed to inhabit this forest area.
Natural or non-selective appearances of melanism in Gray Squirrels may have a
genetic explanation. Recently, McRobie et al. (2009) sequenced the MCIR gene for 3
coat-color phenotypes in the Gray Squirrel, and found that a 24 base-pair deletion in
MCIR is associated with melanism. Coat color is due to varying distributions of eumelanin
and phaeomelanin production. They discovered that MCIR plays a central role in
regulating eumelamin and phaeomelan production, a finding possibly related to the melanistic
coat color in the Gray Squirrel that we observed. They do not rule out, however,
that other genes may contribute to melanism in the Gray Squirrel as well.
In Great Britain, the melanistic squirrel population is increasing in both size and
geographic range (Thomas and Pankhurst 2005). It will be interesting to see if other
melanisic Gray Squirrels are observed in the Georgia Piedmont in future years.
Acknowledgments. We thank Steven W. Seagle and two anonymous reviewers for their
comments on the manuscript.
Banfield, A.W.F. 1974. The Mammals of Canada. University of Toronto Press, Toronto, ON,
Canada. 438 pp.
Creed, W.A., and W.M. Sharpe. 1958. Melanistic squirrels in Cameron County, PA. Journal of
Ducharme, M.R., J. Larochelle, and D. Richard. 1989. Thermogenic capacity in gray and black
morphs of the Gray Squirrel, Sciurus carolinensis. Physiological Zoology 62:1273–1292.
Gustafson, E.J., and L.W. VanDruff. 1990. Behavior of black and gray morphs of Sciurus carolinensis
in an urban environment. American Midland Naturalist 123:186–192.
Innes, S., and D.M. Lavigne. 1979. Comparative energetics of coat colour polymorphs in the Eastern
Gray Squirrel, Sciurus carolinensis. Canadian Journal of Zoology 57:585–592.
Kiltie, R.A. 1989. Wildfire and the evolution of dorsal melanism in Fox Squirrels. Journal of Mammalogy
Kiltie, R.A. 1992. Camouflage comparisons among Fox Squirrels from the Mississippi River Delta.
Journal of Mammalogy 73:906–913.
McRobie, H., A. Thomas, and J. Kelly. 2009. The genetic basis of melanism in the Gray Squirrel
(Sciurus carolinensis). Journal of Heredity 100:709–714.
Nelson, E.W. 1918. Smaller mammals of North America. National Geographic Magazine
Schorger, A.W. 1949. Squirrels in early Wisconsin. Transactions of the Wisconsin Academy of
Science, Arts, and Letters 39:195–247.
Shorten, M. 1945. Inheritance of melanism in Gray Squirrels. Nature 156:46–47.
Steele, M.A., and J.L. Koprowski. 2001. North American Tree Squirrels. Smithsonian Institution
Books, Washington, DC. 201 pp.
Thomas, A.P.M., and S.J. Pankhurst. 2005. The black squirrels of Cambridgeshire. Nature in Cambridgeshire
Thorington, Jr., R.W., and K. Ferrell. 2006. Squirrels: The Animal Answer Guide. Johns Hopkins
University Press, Baltimore, MD. 183 pp.
Whitaker, Jr., J.O., and W.J. Hamilton, Jr. 1998. Mammals of the Eastern United States. Cornell
University Press, Ithaca, NY. 583 pp.