Not afraid of the big bad wolf: calls from large predators do not silence mesopredators

Abstract

Large predators are known to shape the behavior and ecology of sympatric predators via conflict and competition, with mesopredators thought to avoid large predators, while dogs suppress predator activity and act as guardians of human property. However, interspecific communication between predators has not been well‐explored and this assumption of avoidance may oversimplify the responses of the species involved. We explored the acoustic activity of three closely related sympatric canids: wolves Canis lupus, coyotes Canis latrans, and dogs Canis familiaris. These species have an unbalanced triangle of risk: coyotes, as mesopredators, are at risk from both apex‐predator wolves and human‐associated dogs, while wolves fear dogs, and dogs may fear wolves as apex predators or challenge them as intruders into human‐allied spaces. We predicted that risk perception would dictate vocal response with wolves and dogs silencing coyotes as well as dogs silencing wolves. Dogs, in their protective role of guarding human property, would respond to both. Eleven passive acoustic monitoring devices were deployed across 13 nights in central Wisconsin, and we measured the responses of each species to naturally occurring heterospecific vocalizations. Against our expectation, silencing did not occur. Instead, coyotes were not silenced by either species: when hearing wolves, coyotes responded at greater than chance rates and when hearing dogs, coyotes did not produce fewer calls than chance rates. Similarly, wolves responded at above chance rates to coyotes and at chance rates when hearing dogs. Only the dogs followed our prediction and responded at above chance rates in response to both coyotes and wolves. Thus, instead of silencing their competitors, canid vocalizations elicit responses from them suggesting the existence of a complex heterospecific communication network.