Studying acoustic communication in pilot whale social groups

Abstract

Many cetaceans are gregarious animals with a complex group structure, and they depend on acoustic signals for mediating social interactions among individuals. However, the marine lifestyle and closed sound production system makes it difficult to study social signaling in groups of wild cetaceans. Acoustic and movement logging tags offer new possibilities for sampling the sounds and behavior of individuals, but themselves provide new challenges in determining the source of acoustic signals. Here, we draw on experiences from studies of short-finned and long-finned pilot whales to discuss how social signaling can be investigated in wild marine mammals. We discuss how specific social contexts, especially separations from the social group, can aid the interpretation of individual tag data to test whether calls of short-finned pilot whales are important in mediating social contact with group members, while emphasizing the pitfalls of using such methods. Specifically, we highlight the advantages of simultaneously instrumenting multiple closely associated pilot whales with acoustic and movement recording tags. This has improved our understanding of acoustic interactions through ready identification of the sender and simultaneously monitoring the reaction of other group members, and we use this dataset to discuss ongoing challenges of studying social dynamics using simultaneous tag deployments.