• Syrian hamsters are the largest hamsters kept as pets.hamster image by Fotocie from Fotolia.com
  
  Pet hamsters generally fall under two catagories: dwarf breeds (such as Campbell's, Roborovski, and Winter White hamsters) or the much larger Syrian hamsters, which are among the largest hamsters in the world. However, there are also a dozen other species of hamster which live only in the wild, two of which grow even larger than the Syrian.
  
  

Syrian Hamster

• When most people think of "hamsters," they imagine the Syrian (mesocricetus auratus). There are several breeds of Syrian hamsters available as pets, the most popular being teddy bear, longhair and golden hamsters. These hamsters are all descendants of the same breeding pairs of wild Syrian hamsters. Syrian hamsters are now endangered or extinct in their native habitats. All of the Syrian variations reach lengths of 4 to 7 inches, and females typically grow larger than males.
  
  

European Hamster

• Cricetus cricetus, the European hamster, also called the black-bellied or great hamster, is the world's largest hamster--about the size of a full-grown guinea pig. They are rarely kept as pets. Their wild populations are in serious decline, and they are either threatened or endangered throughout their native habitat, which ranges from Russia to Belgium.
  
  

Rumanian Hamster

• The Rumanian hamster, mesocricetus newtoni, is similar in size and appearance to the golden Syrian, but can grow slightly larger, usually reaching 7 to 8 inches in length. It is not domesticated and not generally kept as a pet.