Individual vocal traits of mother and pup fur seals

This study investigates individual vocal traits in three species of fur seal: Antarctic fur seal Arctocephalus gazella, Subantarctic fur seal A. tropicalis, New Zealand fur seal A. forsteri and their hybrids. The attraction calls of mothers and pups were highly stereotyped within each individual and markedly different between individuals. Pup attraction calls (emitted by females) were more variable between individual A. tropicalis and A. forsteri than between individual hybrids and A. gazella. However, such a pattern was not evident for female attraction calls (emitted by pups). Pup attraction calls and female attraction calls were both generally tonal calls overlain with regions of pulses. Female attraction calls had relatively high fundamental frequencies. The importance of individual vocalisations for mothers and pups is best appreciated in relation to maternal fitness and offspring survival: individual vocalisations are favoured by natural selection as they facilitate rapid reunion when mothers return from foraging trips, ensuring maternal resources are not invested in unrelated pups.