Visitors

We have a rat living in the garden, well very near the back door really. Often we see him in the afternoon, pottering around the bird feeder. We tempted him with jam  spread at the entrance to the humane trap, we would like him to move somewhere else....and in the morning we found we had had a visitor.... husband set  him free the first day, then a few days later he was back...Was it the same visitor, how can we tell? Shyness made him curl up, both wore exactly the same prickly jacket in the same size and colour...who knows how big the family is too!