Unlike Red Squirrels, Grey Squirrels are much larger in size and never have tufts on the tips of their ears.
It is widely assumed by people (and indeed we at A-Z Animals have been asked the question many times) that Grey Squirrels hibernate during the winter months.
When the seasons change from summer to autumn, Grey Squirrels begin to forage for food including nuts and seeds which are then buried in the ground or stored in holes in the trees.
Squirrels (unlike dormice and bats) are unable to retain a high level of body-fat which means that they cannot sustain themselves through the winter, even if they wanted to hibernate.
Grey Squirrels can be seen to be active during these colder days but will stay in the comfort of their drey if the weather is bad.