The Development of Respiratory and Diving Ability in the Bottlenose Dolphin Calves of Shark Bay, Western Australia

Abstract

We examined the development of respiratory and diving competence in 44 wild bottlenose dolphin calves (Tursiops sp) in Shark Bay, Western Australia. Analyses of dive durations, dive patterns, and mother-calf synchrony show that the newborn period (0-4 mos.) is markedly different from all ages with both mother and calf diving only briefly (1 min. or less), suggesting that mothers adjust their diving behavior during this vulnerable period. In addition, calves gradually increased diving competence into the second year of life, as seen in increased dive durations and a greater proportion of deep dives; however, there were little changes in diving ability thereafter, even though the minimum weaning age is three (Mann et al. 2000). Thus, while diving competence may not be the final limit on weaning age it is likely a prerequisite for the development of other behaviors that ultimately limit weaning age.