The big guys that are about 5-7" long and weigh 4-7 oz. on average. Their tails are almost bare and their feet have fine fur on the top, but none on the bottom -- just bumpy pads. They can have many different colors and patterns and long or short fur. Syrian hamster sometimes called "golden hamsters" as well as stupid pet-shop nicknames like "black bears," "teddy bears," "fancy hamsters," "Dalmatians," "panda bears," and other dopey or misleading terms. They must live individually by the time they're 6-8 weeks old or they will kill one another. They're the easiest of the species to handle, and perfect for first-time owners. Of course children will need supervision handling any pet, and hamsters are delicate enough to make this especially true. The smaller four species can live in same- or opposite-sex pairs or small colonies if they're same-sex siblings from the same litter or if introduced carefully when young. Their temperaments and habits are different enough that they must live only one species to a cage. Pairs or groups may have to be separated if fights or bullying ensues, so it's essential to have an extra cage on hand just in case.