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）因种群密度极低、生性隐秘且为晨昏-夜行性动物，野外观测难度极高。探索其远程声学通讯或可为该物种种群研究提供高效替代方案。本研究评估了声音回放实验（playback）在野外研究鬃狼中的适用性，并将实验结果与前一年同月同区域开展的20晚被动录音结果进行对比。在6个测试夜晚中，有3个夜晚成功获取到鬃狼的声学回应，其中包含两只个体的应答行为，以及一次互动式声音回放后个体靠近的记录。尽管研究团队每日在不同时段开展了3至6次声音回放实验，但仅在17:00至19:40的实验时段中获取到了声学回应。在被动录音阶段，每台记录仪每晚平均监测到0.86个咆哮吠叫序列（roar-bark sequence），且此类发声多集中于上半夜。声音回放实验夜间的声学活动（包括主动回应与自发的咆哮吠叫序列）几乎是被动录音阶段的4倍。本研究结论表明，声音回放实验可诱导鬃狼发出咆哮吠叫，该方法适用于验证鬃狼行为相关假说，并可辅助其种群监测工作。