There are four species of dwarf hamsters in the pet trade--the Russian or Campbell's, the winter white or Siberian, the Chinese or rat-faced hamster and the Roborovski or Robo hamster. Although they are called dwarf hamsters, this only means that they are smaller than the common pet hamster, the Syrian. Dwarf hamsters are not dwarfs in the sense that they have stunted limbs or any other malformation. Despite their differences in size and appearance, all dwarf hamsters species have similar dietary, housing and exercise needs.
Select a plastic, metal or combination cage specifically for dwarf hamsters. Many commercial hamster cages or habitats are designed for Syrian hamsters. They often have metal bars wide enough for a dwarf hamster to slip through. Since Roborovski hamsters are only the size of ping-pong balls, an aquarium at least 10 gallons large is the best option. Be sure to use a wire mesh lid for ventilation.
Furnish the cage with at least a slow drip water bottle that has a ball bearing at the end; at least one inch thick of bedding; an exercise wheel with a solid bottom so the hamster cannot fall through the rungs; and a hiding place. There are commercially made small animal dens, but an overturned small cardboard box will also work. Replace the box when it gets wet.
Feed a base diet of commercial food made for hamsters, not for any other species of pet rodent. These diets come in pellets, small blocks and a mix of pellets and seeds. It is normal for dwarf hamsters to clean out a food dish, but they are not hungry. They eat only a little bit and then store the rest of the food in small piles around the cage. Good treats for dwarf hamsters include one mealworm per week, an eighth of a teaspoon of plain yoghurt or tofu and small fresh pieces of carrot, broccoli or green beans, according to "Training Your Pet Hamster." Always make sure fresh water is available in water bottles.
Supervise a dwarf hamster's nightly exercise. Dwarf hamsters are nocturnal and are far more active at night. "Training Your Pet Hamster" recommends that dwarf hamsters be placed in an empty, clean bathtub with toys for a half hour in order to get exercise and relieve boredom. Tamer dwarf hamsters like the Chinese may enjoy being handled or playing in hamster balls. Provide as many hamster-safe chewable toys as possible.
Change the bedding at least once a week or when the cage begins to smell. Remove all uneaten piles of food because they can begin to rot. Clean water bottles and any food dishes daily. Safe bedding for hamsters includes aspen wood shavings and recycled paper litter.
Chinese dwarf hamsters need to be kept in separate cages. Other dwarf hamster species can be kept in pairs or small colonies, but another cage should always be handy in case they begin to fight. "Training Your Pet Hamster" notes that dwarf hamsters that had been living together peacefully can suddenly fight for no known reason. Always take your hamster to a veterinarian at the first signs of seizures, wounds or excessive thirst and increased urination. Dwarf hamsters are prone to diabetes, which can be treated through diet and veterinary check-ups.
Never use red cedar bedding for dwarf hamsters. Never place water in a dish. It will soon be fouled by dirty bedding and food. Never place hamster cages near a source of heat or in direct sunlight because the insides can heat up very quickly. Never wake sleeping hamsters because they may bite.