Hamsters are short tailed nocturnal small rodents that come from desert environments. Several genera are seen as pets: Golden (Syrian), Chinese (striped) and Russian (Hairy footed or Djungarian). The commonest pet species is the Golden and these are all derived from just 3 individuals imported into the UK in 1931. In the wild they live a solitary existence in deep burrows with large grain stores. Generally pet Golden hamsters are kept singly to prevent fighting. Mutations have led to the development of a variety of coat colours and a longhaired coat. The smaller Chinese & Russian hamsters are becoming increasingly popular, as they seem to be less aggressive. In the wild these dwarf hamsters tend to live as family groups and can be kept as pairs as pets. Hamsters as pets are relatively odourless and have simple needs. However they can bite and will gnaw through cages. All hamsters have a relatively short life span. Hamsters have large cheek pouches and can carry large quantities of food in them. Males have large testicles, which stick out backwards either side of the tail. They also have dark coloured glands on each flank. Both of these masculine features are commonly mistaken for tumours. Hamster's front long incisor teeth continue to grow throughout life, but the cheek teeth do not. The information given relates to the Golden hamster. Where appropriate differences with the other types of hamster are noted.