Let your hamster go on living the bachelor life if he is of a breed that doesn’t appreciate company. Syrian hamsters, namely, are territorial; they simply refuse to live with others. If you want to give him a companion, the pair will have to live in separate cages.

Place your female hamster in the male’s cage and monitor them as they interact. Generally, females are more aggressive than males, so putting a female in with a male makes him less of a threat — he is in his own territory, not invading hers. The hamsters may fight a little at first, but if it seems excessive or one-sided, remove the female and cage her separately.

Set up a new, fresh, never-used cage for the hamsters to share. Sometimes, when one hamster is introduced to another in an existing habitat, territorial fighting can prevent them from cohabiting. If the environment is neutral ground, however, it makes this type of fighting somewhat less likely. Hide a few small treats in the cage and introduce both hamsters at the same time. By the time they’re done hunting treats, they’ll have become used to one another.

The fastest and most efficient way to stop fighting between hamsters is to physically separate them. Use caution when you do this by wearing gloves to ensure you don’t get bitten or scratched. Move one hamster into a separate cage or tank and give the dueling duo a “cooling off” period of at least a day before you reintroduce them again.

Sometimes hamsters are territorial, which can lead to fighting. While you have feuding hamsters sequestered, clean the main cage they share and replace bedding. Add new toys, like exercise wheels or tunnels, to give your hamsters something to keep them occupied and expend their energy. Place food in dual locations and add an extra water bottle to reduce the potential of fighting for rations.

Sometimes hamsters fight because they’re living in quarters that are too small to accommodate individual space and territory. Consider moving your hammies into a larger cage, one that can be partitioned off into two individual quadrants if they quarrel on a regular basis. Your hamsters will still have companionship without the physical contact.

Hamster fighting can become aggressive, especially if one hamster is much more dominant than the other. If fighting is ongoing or one hamster shows sign of injury, seek veterinary attention and permanently physically separate your hammies. Don’t put another new hammie in with a known aggressor. If you continue to house your hamsters in close proximity, opt for plastic or glass cages rather than ones with open bars, as this too can lead to squabbling.

Hamsters of the same gender, particularly female littermates, often have the best chances for peaceful cohabitation. Make sure you know the gender of mature hamsters before pairing them off — consult a vet if you need to. Accidentally housing opposite-gender hamsters together can result in unintentional breeding, even between siblings.

For the first two weeks of life, baby hamsters are dependent on their mothers for food and warmth. They are blind and their fur hasn’t completely grown in. By the following week, they can see and look like small adults. In their fourth week, they are weaned and their mother starts driving them off. That’s the time to take them out of the cage and separate them by gender.

By the age of 12 weeks, all types of hamsters are mature. However, Syrian hamsters mature by the age of 5 weeks. Because this species is so territorial, you must keep each hamster in a separate cage or there could be fights to the death. Dwarf hamsters can be housed in same-sex pairs, but keep a close eye on them after the 12-week mark. That’s when some dwarf hamsters turn territorial, so you’ll have to separate them.

Syrian hamsters are the largest captive hamsters and the most popular choices for hamster pets, according to the Pet Web Site. Also called golden hamsters or standard hamsters, these members of the rodent family are best kept by themselves, as they can be antisocial and aggressive toward members of their own species. Syrian hamsters sometimes reaching lengths of 7 inches. Their size makes them easier for kids to handle than smaller hamsters. Syrian hamsters require less maintenance than other types, too, another reason why they’re a good choice for children. Teddy bear hamsters are popular long-haired versions of Syrian hamsters.

Of the two types of dwarf hamsters, the most commonly found as pets are the dwarf Campbell’s Russian hamsters. Small and inexpensive, they are social enough to live in pairs. They are quick, and they may nip when annoyed, according to the Pet Web Site, so they are suitable for older children and teenagers. The other type, the dwarf winter white Russian hamster, is similar in disposition to the Campbell’s and may not be a good choice for young children. Russian hamsters are nocturnal and most active in the evening, making them a natural choice for students who are at school during daytime hours. Both types of dwarf hamsters may reach a maximum length of 4 inches. It’s not that a child can’t have a dwarf, but a dwarf is an at-risk first hamster.

Roborovski hamsters are the newest hamsters to be domesticated. They are not widely kept as pets due to their unwillingness to be handled. The smallest of the popular hamster breeds, they grow to only 2 inches in length. Though they are more fascinating to observe than to play with, they rarely nip and have gentle dispositions, according to a Doctors Foster and Smith website. They are social hamsters if they’re kept with others from birth, but they don’t make friends well. Their life spans of 3 to 3 1/2 years make them the longest-lived of the domestic hamsters.

Chinese hamsters, also known as striped hamsters, are uncommon as pets due to breeding difficulties. They look very much like their mouse cousins. They are quite timid and very fast, preferring large spaces to live and hide in. Their slender bodies can reach 12 centimeters in length and their life spans can range from 2 1/2 to 3 years. Chinese hamsters are not sociable with others of their kind, but are good-natured toward their human caretakers, according to Doctors Foster and Smith.