Temporal and spatial patterns of the long-range calls of maned wolves (Chrysocyon brachyurus)

Abstract

Passive acoustic monitoring can aid conservation efforts and elucidate the behavior and ecology of nocturnal/crepuscular secretive species, like the maned wolf. Here we characterize the seasonal, lunar, and nightly patterns in the long-range vocalizations (roar-barks) of free ranging maned wolves at Serra da Canastra National Park (Brazil) throughout eight months of recordings over two years with a grid of 12/13 autonomous recorders. We found an increase in vocal activity coinciding with the mating and the circa-parturition period of the species. Those peaks indicate a role of roar-barks in partner attraction and mate guarding, and in intra-familiar-group communication. Vocal activity happened throughout all recorded periods and was much higher at some sites than at others, suggesting that roar-barks also function to announce territorial ownership and defense. Maned wolves vocalize more around the waxing gibbous lunar phase, and after dusk until mid-night. Moonlight likely reduces foraging time, resulting in more time available to communicate acoustically, while vocalizations early on the onset of activity suggest a territorial announcement function. Group vocalizations did not always follow the general vocal activity pattern, which suggests that social events may require: immediate response, as territorial contests; and/or simultaneous location of animals, as mate guarding, and joint territorial defense. Based on spatial patterns, we estimate between 6 and 11 individuals contributed to the recordings.