Mother–Offspring Vocal Recognition and Social System in Pinnipeds

Abstract

In many species, parents and offspring have developed the ability to vocally identify each other. In avian species, a strong relationship between individual recognition system and social structure has been shown, with recognition systems being more elaborated in species exposed to strong selective pressures (e.g., colonial species vs. solitary species). Pinnipeds (seals, fur seals, sea lions, and walrus) are an excellent mammalian clade model for comparative studies of individual vocal recognition as they present a high diversity in both their social structures and breeding systems, and they use vocal signals in all their social interactions. The investigation of mother--pup vocal recognition systems demonstrates some clear evidence that pinniped species with the highest selective pressures for mother--pup recognition have developed the most complex recognition system. Indeed, such species show a high index of vocal stereotypy (IVS), a rapid onset of vocal recognition, a multi-parametric vocal signature mainly based on temporal analysis whereas species living in less constraining environments show a moderate to low IVS, a delayed onset of vocal recognition, a multi-parametric signature mainly based on a frequency analysis. Our understanding on how ecological and social constraints drive communication systems in vertebrates is essential. Our current knowledge on different taxa show that species encountering similar constraints for individual recognition has developed similar communication systems, suggesting common communication strategies in vertebrates.