Arctocephalus galapagoensis pups became more active as they grew older and always showed more activity during the day than at night. Pups did not forage independently, and continuously lost weight while their mothers were at sea for a maximum of 4 continuous days; nevertheless, the pups' activity level remained constant. Pups were active for more time in the mother's presence, but this was only due to long sucking times. Otherwise, less energetically demanding activities like sitting and lying predominated during the time active and playing and walking appeared to be reduced in the mother's presence. Male pups seemed to be more active than female pups, particularly in play-fighting.-from Authors