ABSTRACT
The longevity of aging rats is influenced by many variables such as the strain or stock, sex, husbandry conditions, breeding history, and diet. The importance of these factors and their influence on longevity have been stressed in reviews. The male wistar-derived (WAG)/Rij rats, unlike the other cohorts of virgin rats, had a shorter life span. The 90% survival age was 13 months, the 50% survival age was 24 months, the 10% survival age was 31 months, and the oldest male was 34 months. Retired breeder Brown Norway (BN)/Bi females appeared to survive longer than virgins. Life span data are not available for males and females and for retired breeders and virgins of all the commonly used strains and stocks of rats. However, most published studies indicate that the 50% survival age is about 27 to 30 months for most strains and stocks of rats.
