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.