Black squirrel

Black morphs of eastern gray squirrels occur most frequently in the northern portion of its range around the Great Lakes Basin.

However, black morphs of eastern gray squirrels form the majority of the species' population in the Canadian province of Ontario, and the U.S. state of Michigan.

Several municipalities and post-secondary schools in the United States have adopted a black squirrel for branding purposes, using it as a symbol and/or mascot.

Some municipalities that have adopted the black squirrels as a symbol for their community have also passed ordinances that discourage attempts to threaten them.

[1] A study published by FEBS Letters in 2014 demonstrated how a pigment gene missing a piece of DNA, can be a determinant of an eastern gray squirrel's coat.

[2] The emergence of black fur in the eastern gray squirrel is believed to be the result of the 24 bp deletion from their melanocortin 1 receptor (MC1R) gene; with the specific allele referred to as MC1R∆24.

[2][9] However, the theory that the black morphs squirrels were more prevalent prior to the 1700s, and that deforestation led to their decline has been challenged by some researchers.

[11] One study found a high frequency of black eastern gray squirrels lived in rural southern Ontario, an area primarily made up of farmland.

[12] Melanism in fox squirrels in the southeast portion of its natural range has also been associated with crypsis, as it inhabits forests that go through periodic burnings.

[14] Additionally, researchers of the color morph have noted a strong negative correlation with the frequency of black squirrels and areas with high air temperature.

[15] The apparent thermal advantage has contributed to the expansion of the eastern gray squirrel's range northward following the end of the last glacial period.

[16] A study published by the European Journal of Ecology in 2019 on eastern fox squirrels found that the melanistic morphs of the species saw a noticeable increase in their surface temperature (fur and skin) in both sunny and cloudy weather; whereas the non-melanistic fox squirrels only saw their surface temperature increase when it was sunny with no cloud cover.

[8] Its ability to gain heat in sunny and cloudy conditions is believed to be the reason why melanistic squirrels are more active during winter mornings.

[22] It has also been suggested that behavioral differences with regard to mating may exist between the urban and rural populations of eastern gray squirrels.

[2] It has been suggested that the frequency of the black color morph in the eastern gray squirrel populations has declined since the late 1700s, especially south of the Great Lakes.

[15] Significant populations of black morphs are also present in the other provinces/states that surround the Great Lakes; with approximately 15 percent of the eastern grey squirrels in those regions reported to be melanistic.

[15] Among exurban populations of eastern gray squirrels, the black morph only occurs in high frequencies in Ontario and northern Michigan.

[3] Although they occur more frequently in the southeastern United States, large populations of black morph fox squirrels may be found in other areas of the species' natural range; including Council Bluffs, Iowa, around the Missouri River.

[27][28][29] There remains a level of uncertainty as to why the black morphs were introduced into the National Mall; although representatives from the Smithsonian Museum suggest their introduction may have been part of a larger effort to revitalize the local eastern gray squirrel population whittled down by human hunting.

[31] He reportedly received 400 eastern gray squirrels from Kent County, Michigan, including some black morphs, and released them into the community.

[21] However, an initiative to reintroduce the black morphs into the squirrel population was undertaken in 1961 by Kent State University, based in Portage County.

According to the story, some of the black morphs later escaped the arsenal by jumping across ice floes on the Mississippi River when it was frozen, and populated the other areas on Rock Island.

[45] Marysville is one of several communities in the United States that have enacted specific legislation to protect the black morph populations, given their low frequency south of the Great Lakes.

[47] Other cities that provide legal protection for black squirrels include Council Bluffs, Iowa; which enacted an ordinance that discourages attempts to threaten them.

Post-secondary institutions typically adopt the black squirrel as an informal mascot for branding purposes, in an effort to further their recognition and visibility and to present an image of a "fun college campus".

[48] The black squirrel has been used as an "unofficial" mascot of Kent State University and Portage County, Ohio, since the late 20th century.