Rats are social animals. They can easily get lonely if they live alone. Rats are nocturnal, and they are most active during the night. Even if pet rats have human companionship, they’ll be alone once humans sleep. Rats need the companionship of other rats.
If they have been left alone for a long period of time, abnormal behaviors may arise.
If two unfamiliar adult rats are introduced and placed in the same cage, aggression may arise. Once they establish a dominance hierarchy, the levels of aggression may drop. Take note that fighting between rats who live in the same cage is a rare occurrence.
Protection from Predators
Rats are often the prey in the animal food chain. It is imperative that they have protection from any sound, sight, or smells of predator species – cats, dogs, birds, ferrets, etc.
Gentle contact on a regular basis allows rats to bond with their humans. Give them treats as often as possible to reward them for their company. With good handling, rats can also trust their humans enough to be trained. Avoid handing them into other unfamiliar people since this will stress them out. Do remember also that rats are nocturnal; it is best if they are handled when they are awake.