Very Large Squirrels

I don’t know where to post this but I have a burning question: Why do some Eastern Grey Squirrels grow to be three times the size of most Eastern Grey Squirrels?

I live in an area where there are a lot of these grey squirrels. I watch them every day in my backyard. But three times this spring I have seen huge animals in trees in the neighbour that I was sure must be some other species. Yet each time I am told that they are Eastern Grey Squirrel.

I have no way to weigh or measure these animals or to physically compare them in side-by-side comparisons for others to see. And no one seems to believe me about their size. But everyone insists the pictures I post are Eastern Grey Squirrel.

Do these animals find steroids? I live in a downtown area where all kinds of stuff is available for humans but wild animals…

UPDATE: Regarding location, I live in Southern Ontario, Canada. I posted one of these squirrels and the coordinates on this observation:

April 24 2022

May 1 2022

For comparison, here’s an ordinary squirrel seen in a tree the same day.

May 7 2022


I, for one, welcome our squirrel overlords.


I’m not sure where you live, but it’s possible that they are Fox Squirrels. Fox squirrel - Wikipedia

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Sounds interesting, if you can ever get a side by side photo, I’d love to see these rodents of unusual size


Agreed, would help to know your location as more than one species might be present.


Just scanned your observations. There’s not much in those photos to indicate the size of the squirrels or their coloration. You seem to be right at the northern limits of fox squirrel distribution, so it’s possible you have some of them. Photos showing fur color would really help, as would photos with something indicating the animal’s size (a fencepost, for instance).

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I updated my post with coordinates and photos. What, if anything, can you tell me?

Thanks for your research. I updated my post with photos, including one regular grey squirrel in a tree for comparison. I am hoping the tree limbs will serve for scale since that is the best I’ve got. We have red squirrels here but they are much smaller than the grey squirrel and not as plentiful. Here are a few photos with the fence for scale.

American Red Squirrel, May 2 2022

Grey Squirrel, April 29 2022

Grey Squirrel running along fence, May 5 2022

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Maybe you’re seeing gravid females which appear heavier.


In addition to the pregnancy explanation, it may be that some of the slimmer squirrels have already molted their winter coats and the larger ones have yet to to molt. For comparison, this is the same individual Eastern Gray Squirrel in a winter coat and summer coat (photo from reddit):


I agree with Eastern Grey squirrel.It may be a pregnant female that hasn’t molted. If if was cold that morning she may also have fluffed her coat.
I believe the photos lighted well enough that the color of fox squirrel would have shown.


Pregnancy or molting, etc. cannot possibly explain what I’m seeing. The difference between looking at these very large squirrels and regular Eastern Grey Squirrel is like looking at an overweight six-foot four-hundred pound man versus a regular 5 foot 6 woman weighing in at 130 pounds. Pregnancy, weight gain, and winter coat cannot possibly make you mistake one for the other.

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Maybe many factors are being combined here…

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Since no one here can explain it I’m going to look up an expert locally. Someone else must be aware of this animal and know something about it. Thanks for all your input.

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When they get pregnant they do get pretty big.

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Maybe fatter, but not taller and longer. I’m submitting my photos to the Ministry of Natural Resources of Ontario to see what ID they come up with.


Don’t forget to let us know what they say. Now we’re curious, too!


If you recall East German competitive swimmers from the 60s and 70s, I think you will have your answer.

(Yes, this is a joke.)


Dr. Jeff Bowman (not related to me) of the Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry examined the photos. He says:

I can say with confidence that the black squirrels in your picture are the same species as the gray ones you see running around. They are a black form of the eastern gray squirrel, Sciurus carolinensis. They can get really big of they are living close to a bird feeder, or some other supplemental food that allows them unlimited access.

I did not have a good enough picture of the grey one for him to identify but I am confident that it is the same animal, just another colour.

So now I have an official explanation for their size. That is what I wanted–a name for the animal and a reason for their size.


This has been resolved but for the sake of answering one of the subsidiary questions raised in the discussion, fox squirrels have a very limited distribution in Ontario. Unless things have changed recently, they are only found on Pelee Island, in Lake Erie.