Consistent decisions of a predator facing potentially poisonous prey

Decision making has important fitness consequences in domains as varied as foraging, mating and predator avoidance. In noisy ecosystems, animals often inform their decisions via information streams that may span sensory modalities. Despite theoretical predictions, we have little understanding of whether attending to multiple cues enhances decision-making performance or reduces it by creating cognitive overload. The predatory fringe-lipped bat, Trachops cirrhosus , hunts by eavesdropping on auditory prey cues, but it utilizes information from other sensory modalities when challenged in the laboratory and rapidly adopts new hunting behaviours through social learning. When hunting frogs, it uses their calls to identify palatable species. Túngara frog, Engystomops pustulosus , males court females with a multimodal display: their calls (auditory) and the simultaneously inflating vocal sac (visual) create water ripples (seismic). Here we evaluated decision making in fringe-lipped bats attending to ambiguous stimuli with and without additional cues. We quantified foraging decisions in response to synthesized hybrid calls spanning a gradient from calls of the palatable túngara frog to those of a poisonous toad. Hybrid calls were presented to bats in silence and with additional stimuli: social cues (conspecific chewing noises), environmental noise (anuran chorus) and additional cues associated with target frog calls (vocal sac motion and water ripples). We predicted (1) social and target cues would make hybrid calls more attractive as a potential food source and (2) decision making would be slower in the presence of noise. Counter to expectation, bats maintained highly consistent responses to hybrid stimuli regardless of treatment, supporting neither the enhanced performance hypothesis nor the cognitive overload hypothesis on decision making. We observed flexibility in minimum approach thresholds, however. Bats showed greater exploratory and risk-taking behaviour when given access to information in the form of target cues in noise. Our results elucidate how cognitively complex animals deal with information complexity in varying decision-making contexts. • A robotic frog presented prey calls blending signals from edible and toxic species. • Bats made consistent foraging choices regardless of additional cue types. • Bats attacked calls that sounded more palatable more quickly and frequently. • Social and multicomponent cues encouraged exploration of riskier prey. • Bats showed cognitive flexibility in ambiguous decision-making contexts.