Conclusion: these studies found that castrated rats lived slightly longer than a similar group of intact rats. Castration is not, of course, a guarantee of longer life for an individual rat. Rather, considered as a group, castrated rats have a moderately longer average lifespan than a similar group of intact rats. However, other factors, such as exercise, mating, and restricted food can prolong life even more than castration when compared to similar groups of control rats. Longevity is subject to a wide variety of factors, and hormonal state is just one of the many variables that plays a role in determining how long an individual might live.