Physiological synchrony among human fishers during collective hunting with wild dolphins.

Predator physiology is often overlooked in predator-prey interactions, despite its potential to significantly influence hunting dynamics and social cooperation among predators. We address this gap by investigating how physiological alignment relates to group dynamics and hunting performance in a unique interspecies mutualism: artisanal net-casting fishers who target fish with assistance from wild dolphins. We monitored 24 fishers using high-resolution chest-belt sensors, recording continuous electrocardiograms (ECG) and GPS positions. We then calculated interpersonal heart rate variability (HRV) synchrony in low (LF) and high frequency (HF) bands while tracking changes in foraging and social contexts. In both LF and HF HRV domains, positive social factors increased HRV synchrony among fishers, especially those with established cooperative bonds, whereas distance between fishers decreased HRV synchrony. External factors-the presence and activity of dolphins-had no measurable impact on HRV synchrony. We also found a negative association between group-level hunting success and HRV synchrony in the LF domain, which is influenced by both sympathetic and parasympathetic activity. By demonstrating the role of physiological synchrony during collective hunting in humans-driven by social factors and with direct implications for hunting outcomes-our study advances the current understanding of the eco-physiological dynamics of social predators in predator-prey systems.