The ancient rat.

The past decade has seen an increase in the number of rodents being kept as pets and subsequently in the number of rodent owners seeking veterinary services. The common rat, (Rattus norvegicus) has become increasingly popular, particularly as novel varieties have been introduced to the pet market. The average laboratory or domestic pet rat has a life expectancy of approximately 2.5 to 3 years although 4 years and longer have been reported. As an increasing pet rat population ages, more owners are seeking veterinary consultation on various geriatric rat diseases. This article is an introduction to common rat geriatric diseases.