Syrian or golden hamster (Mesocricetus auratus)

An interesting use of hamsters in medical research is the study of the neural basis of our internal daily (circadian) rhythms - in humans  this controls our sleep-wake cycle over a 24hr period. The control centre for these rhythms was found in the hypothalamus of the brain, and the use of hamsters clearly demonstrated the role of the hormone melatonin in this daily cycle. [4,143]