Dwarf hamster breeds are among the smallest domesticated rodents. Dwarf hamsters are commonly between 2 and 4 inches long; the largest weigh no more than 2 ounces; the smallest, a half-ounce. They live in cages and a little bit of maintenance daily to stay healthy. Dwarf hamsters are more social than their larger counterparts, the Syrian hamsters, but that does not mean dwarf hamsters are social pets.
Hamsters Are Not Social
It is normal for hamsters behave aggressively towards other animals. Hamsters are often territorial and often view any other animals within their environment as threats. Dwarf hamsters can be kept together in a cage with companions so long as the cage mates are introduced at a young age and are the same species, same gender and same approximate age. Littermates are your best bet for a harmonious habitat. Your dwarf hamsters are probably going to feel threatened and behave aggressively or react fearfully to other adult hamsters or any other types of animals.
Hamsters are prey animals. This means that in the wild, your hamster is naturally the animal that gets eaten by larger carnivores, such as cats and birds of prey. Your hamster's natural instinct toward a predator such as a cat should be to run away from it and hide until the threat goes away. If the hamster is unable to escape from the cat, he may behave aggressively in order to attempt to protect himself. It is normal for your hamster to be afraid of your cat. Your hamster may also become very stressed and unhappy if placed in a location where the cat has access to the hamster cage.
It is your cat's natural instinct to want to prey on your tiny dwarf hamster. This means that your cat may want to chase your hamster, play with it in a very aggressive manner and possibly eat your hamster if given the opportunity to do so. It is not practical to attempt to train the natural instinct to hunt out of your cat, though you should reprimand your cat verbally if you see him displaying aggressive, hunting behavior towards your hamster.
Hamsters and Cats in the Same Home
Your dwarf hamster should always be kept in a locked cage that your cat can not get into. If your cat is especially interested in the hamster and attempts to get to the hamster through the cage, then the hamster will need to be placed in a location that your cat can not access. If you leave your hamster and cat together unattended, natural instinct may kick in -- and you may not have a hamster when you return.