Grey squirrels are known to be less arboreal, in other words, to spend less time in trees than their red counterparts. Red squirrels are therefore more elusive. However, both species of squirrel are known to produce two litters of 2-4 young between February and July if there is a good supply of food available. The newly born squirrel will only emerge from the nest at about 7 weeks. It is around this time they also start eating solid food and are usually abandoned or left by their mothers, however, they will stay in the same area as their young until at least autumn comes around. Even though it is rare, some do nest with their mothers over the winter months.

Squirrels only really fight one another during the mating or breeding season and the dispersal seasons. This involves both chasing and wrestling with one another. These fights usually happen between the males directly over a female squirrel where it is common to see up to 7 males around one female vying for dominance. The squirrel is also known to emit up to 11 different calls. These noises are broken down into categories such as scolding and angry noises. Squirrels may also indicate to one another the presence of a predator through these noises combined with flicks of their tales.