sport in England and France called rat-baiting. It involved combining 100 to 200 recently trapped wild rats and a trained terrier in a pit. The spectators wagered on how length of time it took the dog to kill all the rats. Of course, these spectacles required the collection of large numbers of animals. Inevitably, albinos were trapped. These white Norway rats were then saved and bred for future exhibition (6:1-6). By the mid-nineteenth century, the albinos were being used in scientific experimentation (2:47-54).
An individual Norway rat can live over 3 years. The average life span for the species is rather broad. It ranges from 2.5 to 3.5 years (2:47-54).
Rats are a communal organism. As long as it remains uncrowded, several males and females may be kept together in one cage. Fighting among adults occurs rarely.
In captivity, Norway rats breed all yearlong. Females can produ
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