Eastern gray squirrels have alarm vocalizations associated with predator-type. One of the strongest associations is that alarm-calling squirrels typically produce moans for aerial predators and quaas for terrestrial threats. One commonly-supported hypothesis for such predator-associated signals is that they elicit predator-specific escape responses in conspecifics. We first tested whether gray squirrels use distinct escape behaviors for aerial versus terrestrial predators by simulating predator attacks using a glider, shaped and painted to resemble a Cooper’s hawk, and a wheeled model cat. We then played back recordings of quaas or moans, matched for number of vocalizations, amplitude, and overall duration to individual foraging squirrels and recorded their responses.
Results/Conclusions
With simulated aerial predators, squirrels ran to the far side of tree trunks. In response to simulated terrestrial predators, squirrels frequently ran to where they could see the predator but could quickly flee to the far side of the tree trunk. Playbacks of quaas and moans elicited flight behavior, but there was no association between escape location and alarm call type. Locations to which squirrels fled in response to alarm calls differed from those in response to simulated predators, with squirrels pausing on the side facing the call’s source. While gray squirrel alarms and escape strategies differ by predator type, the vocalizations do not function to elicit divergent escape strategies in conspecifics. This result stands in contrast to observed functions in other species with calls differing by predator type.