Squirrels aren’t rare in Russian urban parks and suburban forests but they are leaner and more agile than their East Coast counterparts, thus a little harder to photograph but also less likely to find in garbage cans. Plus, a difference in color: in the US Southeast at least, squirrels seem greyish or brownish with fluffy, semi-transparent bluish-silvery tails. This one is red with a brown tail.
Speaking of agility, lots of American urban squirrels are lazy and overweight like Moscow pigeons of twenty years ago. I remember a bunch of squirrels in Washington, DC, not far from the Vietnam memorial, so fat they could only waddle slowly. Offer a walnut to a Russian park squirrel, and it’ll run up to you, snatch the offering from your open palm, run off and start nibbling at it at a safe distance. Try the same in DC – I’m not sure they’ll be interested at all.
Being an ignoramus in biology (“what do you mean, there are different kinds of trees?”), I used to think American chipmunks were baby squirrels. That fit my picture of the worlds quite well: Russian chipmunks live in Siberia, where they pester geologists, begging for sweet condensed milk (sguschonka), so no way can these exotic lovelies be seen side by side with rather prosaic squirrels.