10 - Development

Summary

Development in elephant seals intrigues us because pups receive no training from adults or peers, they embark on sex-specific reproductive strategies early in life, and they must transition to foraging at sea. Young males obtain more milk energy than females, which increases their size and enhances the probability of breeding in adulthood. Pups learn how to swim and dive and forage on their own and they are naïve about prey and predators when they go to sea for the first time. Most pups die during the first two trips to sea; those that survive do not increase their weight, suggesting that foraging is difficult. By the end of the second year, the location and pattern of diving are similar to those of adults, and sex differences in dive pattern begin to appear. The transition to becoming a diver, both in behavior and physiology, is rapid.