Meet me in the middle: potential collaborative benthic hunting in humpback whales (Megaptera novaeangliae)

Abstract Cooperative hunting, in its numerous forms, has implications for animal cognition and social evolution. We used multi-sensor acoustic/video recording tags attached to free-swimming humpback whales (Megaptera novaeangliae) to provide the species’ first documentation of cooperative, coordinated benthic hunting and evidence supporting collaboration, the most cognitively complex level of hunting. Collaborative hunting, consisting of the tagged whale and 1–3 co-hunters, comprised 79% ( n = 110) of observed benthic-hunting events. Hunting animals concurrently arrived at the seafloor and simultaneously moved towards co-hunters, forming a head-to-head configuration that terminated when rostrums were within meters of each other; a behavior that could be seen to drive/corral sand lance ( Ammodytes dubius ) prey towards co-hunter(s). Tagged animals changed their direction of attack for each event, but co-hunters typically realigned into the same relative position, based on that of co-hunters. Using a clock position method, in relation to the tagged animal’s heading (12:00; n = 87), co-hunters occupied the 1:00 position most frequently (59%), followed by 11:00 (35%), 12:00 (12%), 3:00 (5%), and 2:00 (2%). The 1:00 and 11:00 locations would be optimal prey herding/capture positions. In events where all co-hunters were identified, individuals assumed the same position in 93.1% of events ( n = 54). Animals opened their mouths for prey capture in near unison (mean offset 3.7 s, SD 5.3 s, n = 43). The fission-fusion, non-kin-based social system of humpback whales makes them an unlikely species to evolve collaborative hunting. We speculate that the need to capture small, evasive prey, combined with cognitively driven behavioral plasticity contribute to the evolution of this hunting strategy.