Life History of Pinnipeds. In: The Encyclopedia of Marine Mammals (3rd Edition)

The life history of an individual is the pattern of allocation of resources to maintenance, growth, and reproduction throughout its lifetime. Life history analysis attempts to explain the scheduling of the allocation process throughout an organism’s life which maximizes fitness. Life history is measured across time linking reproductive rates with measures of growth or body condition. Most life history studies involving pinnipeds have assumed that age is the main force in pinniped life histories, but age per se may have relatively little to do with influencing fitness. Other factors like body size are likely to be more important than age. Body size has been recognized as a determinant of sexual maturity in pinnipeds. Consequently, age at sexual maturity in pinnipeds may decline as growth rate increases. This could mean that the food available to a population of pinnipeds might change the average life history.