Using playbacks to monitor and investigate the behaviour of wild maned wolves

Maned wolves are difficult to observe in the wild because of their low densities and their cryptic and crepuscular-nocturnal habits. Exploring their long-range acoustic communication may offer an efficient alternative to study the species. Here we evaluated the applicability of playbacks to study maned wolves in the wild and compare the results with 20 nights of passive recordings on the same area and month during the previous year. We obtained vocal responses on 3 of 6 nights tested, including responses involving two animals and an approach after an interactive playback. Although we conducted 3–6 playback sessions each day at different times, we only obtained vocal responses during sessions between 17:00 and 19:40. During our passive recordings we detected on average 0.86 roar-bark sequences per recorder per night, mostly during the first half of the night. Vocal activity – responses and spontaneous roar-bark sequences – during playback nights was nearly 4 times greater than during the passive recordings. We conclude that playbacks stimulate maned wolves to emit roar-barks and that this method is applicable to test hypotheses about maned wolf behaviour and aid in their monitoring.

鬃狼（maned wolf）野外观测难度极高，原因在于其种群密度极低，且生性隐蔽、兼具晨昏夜行习性。探索该物种的远距离声学通讯机制，或可为其研究提供高效可行的替代方案。本研究评估了野外应用声音回放实验（playbacks）研究鬃狼的可行性，并将实验结果与前一年同月同区域开展的20晚被动声学录音（passive recordings）结果进行对比。本次实验共设置6个测试夜，其中3个夜晚成功记录到鬃狼的发声响应，包括两只个体的应答行为，以及交互式回放实验后个体靠近声源的行为。尽管研究团队每日于不同时段开展3至6次回放实验，但仅在17:00至19:40的实验时段内获取到发声响应。被动声学录音（passive recordings）阶段，每台录音设备每晚平均记录到0.86次咆哮吠叫序列（roar-bark sequences），且此类发声多集中于前半夜。回放实验夜的声学活动（包括诱发响应与自发咆哮吠叫序列）强度近乎为被动录音阶段的4倍。本研究结论表明，声音回放实验可有效刺激鬃狼发出咆哮吠叫，该方法可用于验证鬃狼行为相关假说，并可为其种群监测提供助力。