Three of my rats were six months old when I introduced a six week old rat (Hazel) into their group. They've been living happily together for around three or four months and I've noticed over the last month that Hazel has seemingly started copying one of the others' (Ginger's) behaviour. It's only one, so I was wondering whether they can learn and copy the behaviour of others or whether she just happens to have the same interests/ behaviour as Ginger?