Q: My husband and I walk in a public park in central Alabama where there are lots of gray squirrels. According to what I have read about eastern gray squirrels, it’s not uncommon for them to have “an occasional red tinge.” Recently, however, we have seen several squirrels with a decidedly reddish tint to their tails and hindquarters. We have also seen a few with an overall reddish color. Do you know why some of these gray squirrels look more like something that should be called a red squirrel or at least a reddish-gray squirrel?
A: A simple explanation exists for why reddish-colored gray squirrels might be present in a park in the southeastern United States. Several genes control coat color in eastern gray squirrels, and a particular combination has occurred to produce squirrels with reddish tails, flanks, or even over the whole body. Such changes could occur randomly over a couple of generations. The color might have been absent in the population a few years before.
According to the book “Squirrels: The Animal Answer Guide” (Johns Hopkins University Press) by Richard W. Thorington Jr. and Katie Ferrell, “in urban and suburban areas, there are frequently several color forms of the eastern gray squirrel.” Among the most common variants are “gray” squirrels that have solid black, white, reddish, or even silver coats. One reason these nongray colors might be more common in some areas is that people often develop a community pride about their odd-colored squirrels.
For example, the black, or melanistic, morph of the gray squirrel is common in some northern states and Canada. In the early 1900s 18 individuals were transported to the National Zoo in Washington, D.C. solely because they were an oddity. By the 1920s a regional book on mammals noted that they had spread in the area, and by the 1980s R.W. Thorington recorded the presence of black squirrels outside the Beltway in Maryland and Virginia. I have previously reported about my own experience with the large population of black squirrels that lives on the Kellogg Biological Station in southern Michigan. Although now a famous ecology field station of Michigan State University, the 700-acre area was originally the estate of W. K. Kellogg of Corn Flakes fame. The story I heard many years ago was that Kellogg was fascinated by the black morph of gray squirrels that was found in small numbers in the area. Using his own style of natural selection in the form of a shotgun, Kellogg eliminated the gray individuals and let the black individuals live and reproduce. Although they seem to be as eager to become roadkill as the gray ones, the black phase is now the prevalent color pattern in the region.
Populations of white squirrels are also reported here and there across the country and would probably have low survival chances in the wild because of being such visible prey. However, being associated with humans has its advantages. As with the black squirrels, white ones may become more abundant in a neighborhood than the normal gray phase because people make special efforts to protect them. A white pelage can result from albinism in which the individual has pink eyes or from other genetic expressions, such as one called leucism in which the pigment is reduced but the eyes are blue. A silver-haired morph with dark eyes occurs in the DC area. Who wouldn’t want to try to keep squirrels around that looked as dramatic as some of these, even if they ate your birdseed?
Although black or white populations of gray squirrels are obvious in some communities around the country, I do not know of one in which the reddish color predominates. However, this could easily happen if the color of the coat is inherited and natural selection in the form of predation or even human intervention results in the gray phase being less likely to survive and reproduce. Perhaps one day people will be walking through your park wondering why the gray squirrels are red.
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Whit Gibbons is an ecologist and environmental educator with the University of Georgia’s Savannah River Ecology Laboratory.