Dahl, C. D. | bioRxiv Science

bioRxiv2019

An information-theory approach to geometry for animal groups

One of the hardest problems in studying animal behaviour is to quantify patterns of social interaction at the group level. Recent technological developments in global positioning system (GPS) devices have opened up new avenues for locating animals with unprecedented spatial and temporal resolution. Likewise, advances in computing power have enabled new levels of data analyses with complex mathematical models to address unresolved problems in animal behaviour, such as the nature of group geometry and the impact of group-level interactions on individuals. Here, we present an information theory-based tool for the analysis of group behaviour. We illustrate its affordances with GPS data collected from a freely interacting pack of 15 Siberian huskies (Canis lupus familiaris). We found that individual freedom in movement decisions was limited to about 4%, while a subjects location could be predicted with 96% median accuracy by the locations of other group members, a pattern mediated by dominance, kin relations, sex, the relative time of the day and external events, such as feeding. We conclude that information theory-based approaches, coupled with state-of-the-art bio-logging technology, provide a powerful tool for future studies of animal social interactions beyond the dyadic level.

animal behavior and cognition↗

bioRxiv2019

Machine learning reveals adaptive maternal responses to infant distress calls in wild chimpanzees

Distress calls are an acoustically variable group of vocalizations ubiquitous in mammals and other animals. Their presumed function is to recruit help, but it is uncertain whether this is mediated by listeners extracting the nature of the disturbance from calls. To address this, we used machine learning to analyse distress calls produced by wild infant chimpanzees. It enabled us to classify calls and examine them in relation to the external event triggering them and the distance to the intended receiver, the mother. In further steps, we tested whether the acoustic variants produced by infants predicted maternal responses. Our results demonstrated that, although infant chimpanzee distress calls were highly graded, they conveyed information about discrete events, which in turn guided maternal parenting decisions. We discuss these findings in light of one the most vexing problems in communication theory, the evolution of vocal flexibility in the human lineage.

animal behavior and cognition↗