Melanism

Black Squirrel (Gray Squirrel)

The last couple of posts have been about white wildlife, so naturally I felt that now was a good time to cover black wildlife.

If a white animal is called leucistic, what is a black animal called?  The answer is- melanistic.

Melanism is the fairly rare condition of having predominantly black pigment on skin or fur.  This is a mutation when it occurs on animals that are not normally black in color.  Melanism seems to be more adaptive than leucism because usually it is harder to see a black animal than a white animal (if the animal isn’t in the snowy polar regions, anyway).  Melanistic individuals would not be seen by predators as easily as leucistic individuals; perhaps this means more of them survive.

I’ve only photographed one melanistic animal species- Black Squirrels.  These are melanistic versions of the common Gray Squirrel, and calling them Black Squirrels acknowledges this coloration as a particular ‘color morph’ or phase of the Gray Squirrel species.  Here’s one I saw in a local park a couple of years ago:

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Black Squirrels are an interesting phenomenon.  Unlike leucistic squirrels, Black Squirrels seem to have been the normal coloration of what we now call Gray Squirrels!

The black subgroup seems to have been predominant throughout North America prior to the arrival of Europeans in the 16th century, since their dark colour helped them hide in old growth forests which tended to be very dense and shaded. As time passed, hunting and deforestation led to biological advantages for grey coloured individuals. Today, the black subgroup is particularly abundant in the northern part of the eastern grey squirrel’s range. This is likely due to the significantly increased cold tolerance of black squirrels which lose less heat than greys. Black squirrels also enjoy concealment advantages in denser northern forests.

This is a great example of adaptation at work!

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There are good-sized populations of Black Squirrels in certain areas of Canada and the northern United States (and even Britain!).  Some towns are proud of them.  I can attest to the fact that Ohio has a decent amount.  I’ve seen scattered individuals around central Ohio, and there’s a group in a certain neighborhood of Columbus I’m familiar with that has multiple members and can be seen together on occasion.  The majority of the time I see them however, they mix in with the resident Gray Squirrels.

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Here’s one that I see repeatedly in a particular patch of woodland in a certain park.  I see him more often than I don’t, so this must be this squirrel’s home.  Looks comfy enough 🙂

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Interesting fact- there are jet black Black Squirrels, and there are grayish-black Black Squirrels.  It depends on how many copies of the melanistic gene that a particular individual has.  Here are examples of both I’ve seen:

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The prevalence of Black Squirrels within the Gray Squirrel population has been estimated as high as 1 in 10,000.

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It’s an interesting variation and adaptation that goes to show you that nature is always pushing the boundaries.  Sometimes the results are fruitful and neat to see.