Tables of animal lifespans typically show durations of survival by adult members of a species. However, most individuals die much sooner , before reaching maturity. This is a simple consequence of the fact that females give birth to far more offspring than can survive to reproduce in a stable population. For instance, while humans can produce only one child per reproductive season (excepting twins), the number is 1-22 offspring for dogs ( Canis familiaris ), 4-6 eggs for the starling ( Sturmus vulgaris ), 6,000-20,000 eggs for the bullfrog ( Rana catesbeiana ), and 2 million eggs for the scallop ( Argopecten irradians ). [SolbrigSolbrig, p. 37] Take a look at this figure from Thomas J. Herbert's article [Herbert] on r and K selection illustrating extremely high infant mortality for "r strategists." Most small animals like minnows and insects are r strategists.