Researchers Explore the Reason Black Squirrels, a Remnant of Old-Growth Forests, are Now Common in Cities

Black squirrels, a remnant of olden, old-growth forests, are presently common in cities, and to know the reason further, researchers now want to track the color of squirrels in the backyard.

In the early 1900s, Discover Magazine recently reported, "an international trade deal was brokered" between the United States and Canada.

Frank Baker, the Washington, DC-based Smithsonian National Zoo superintendent, worked on the deal for quite some time.

In a letter dated back in 1900 and was sent to numerous addresses in Ontario, Canada, the zoo superintendent explained he is quite eager to obtain a specific animal for National Zoo and was looking for a contact who could "furnish these animals."

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(Photo: Streeter Lecka/Getty Images)
Black squirrels, a remnant of olden, old-growth forests, are presently common in cities, and to know the reason further, researchers now want to track the color of squirrels in the backyard.

Black Squirrels Found in Canada but Missing in DC

In his 1902 report to the US Congress, Smithsonian Secretary Samuel Langley verified receipt of eight of the desired animals from Rondeau Park on the Ontario-based shore of Lake Erie in exchange for some animals from DC.

According to the said report, squirrels, particularly black squirrels and not just any squirrel, were animals found in Ontario, Canada but were missing "350 miles south in DC."

Anyone who would visit Washington DC to date would not find it hard to spot a black squirrel. These animals are presumably offspring of squirrels that were introduced from Canada.

Nevertheless, if residents are asked in other areas of eastern North America when it comes to squirrels' color, their responses will rely on where they live.

Residents in either rural or suburban locations of the northeastern US or southeastern Canada will perhaps say that the color of squirrels is gray.

The official common name of this species, as a matter of fact, is Eastern Gray Squirrel. However, if one is to talk to anyone living in Detroit or Toronto, he is likely to say that most squirrels are black, and some are gray.

Then, if one could walk through the northeastern US's old-growth forests 200 years back, you would likely see that most of these animals were black.

Reason for Existence of Black Squirrels

Experts in squirrels say the gray and black versions of eastern gray squirrels "are simple genetic variants," a melanism form raises the dark pigment in their fur.

Furthermore, since coat color is hereditary, any changes in each morph's prevalence over time or between cities may be the outcome of biological evolution.

What the researchers are trying to look at now is the reason for the coat's color change.  One researcher initially got interested in squirrel coat color. There is a huge population of black squirrels in New York, his workplace, but only a few black squirrels in the rural forests outside the city.

Scientists call this color change in a trait together with an ecological gradient a "cline." To test if clines in squirrel melanism are typical along urbanization slopes in several cities, the scientists developed the SquirrelMapper, a squirrel-tracking citizen science project.

This enables people from any part of the world to submit location-tagged pictures of squirrels to the mobile app iNaturalist with more than 56 million sightings of all types of organisms.

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