Vervet Vocal Repertoire in an Impacted Environment at Gorongosa Park: Implications for the Evolution of Human Language

黑长尾猴（Chlorocebus pygerythrus）以其使用功能性参考捕食者特定警报呼叫而闻名。由于它们与人类语言的相似性，它们的警报呼叫也经常被讨论人类语言的进化-特别是与围绕高级人类交流起源的声音与手势模式的辩论有关。我们语言的起源是否可以追溯到一种更简单的声音交流形式，比如长尾猴，或者非语言交流是语言最初发展的跳板？对声音起源假说的批评主要集中在假设非人类灵长类动物的声音交流缺乏灵活性，以及遵循简约原则的早期人类声音交流。然而，各种观察表明，非人类灵长类动物的声音交流可能比以前想象的更适应和复杂。莫桑比克戈龙戈萨国家公园的长尾猴为进一步研究自由放养的灵长类动物声音交流的灵活性提供了一个独特的机会。莫桑比克内战后，戈龙戈萨国家公园的豹（Panthera pardus）--一种天然的长尾动物捕食者--数量严重下降。恢复计划正在进行中，并计划在不久的将来将豹子重新引入公园。与此同时，目前的黑尾长尾雉缺乏主要的捕食者。这种“准实验”的情况提供了一个独特的机会，研究的适应性vervet声乐生产和感知的生态转变捕食风险。当这种灵长类动物的声音信号靶点缺失时，它们的声音系统会发生什么变化？传统上与豹子有关的警报呼叫在这些种群中是否不存在，或者它是否在感知到其他威胁时灵活地产生和解释？此外，当豹子重新引入该地区时，长尾猴的交流会发生变化吗？这将如何影响公园中的其他物种，如狒狒（Papio ursinus/cynocephalus），它们通常会利用长尾猴的警报叫声来预测威胁？2019年，在进行必要的安排和改进我的研究方法后，我将前往戈龙戈萨，通过观察长尾猴，寻求回答这些问题。在这样做的过程中，我将阐明黑长尾猴报警呼叫生产和感知的灵活性，以及更广泛的灵长类动物的声音交流，这反过来又将告知人类语言的起源和进化的模型。在计划中的豹重新引入过程中，将选择暴露于各种捕食水平的黑长尾猴部队并进行数月的比较。将通过焦点跟踪和随意采样技术记录（长尾猴和邻近狒狒）的发声和随后的反应，同时收集关于叫声背景的详细信息，包括捕食者的存在、可见的其他同种数量以及信号员的人口统计学因素。通过采用这些实地考察方法，我将获得所有必要的信息，对收集到的数据进行分析，并为我的研究问题提供答案，无论重新引入的规模如何。除了直接有助于灵长类动物交流和人类语言起源的研究外，该项目将与豹重新引入计划密切合作，这将使人们更加关注公园的恢复，并使正在进行的保护项目受益;同时为当地社区提供机会，并通过行为观察和人口普查扩大我们对戈龙戈萨研究不足的长尾猴的了解。

The vervet monkey (Chlorocebus pygerythrus) is well-known for its use of functionally referential predator-specific alarm calls. As well as being of interest in their own right, due to their apparent similarity to human words, the alarm calls of vervets have frequently been discussed in regard to the evolution of human language - being especially relevant to the debate around a vocal versus gestural mode of origin for advanced human communication. Can the beginnings of our language be traced back to a simpler form of vocal communication such as that present in the vervet monkey, or was non-verbal communication the springboard from which language first developed? Critiques of the vocal origins hypothesis focus on the assumed lack of flexibility of non-human primate vocal communication and, following the principle of parsimony, early human vocal communication. However, various observations indicate that non-human primate vocal communication may be far more adaptable and complex than was once thought. The vervets of Gorongosa National Park, Mozambique, present a unique opportunity for further investigation of the flexibility of vocal communication in a free-ranging primate. Following the civil war in Mozambique, the leopard (Panthera pardus) - a natural predator of the vervet - has experienced a severe decline in population at Gorongosa National Park. Restoration programmes are underway and plans are in place to reintroduce the leopard to the park in the near future. In the meantime, the current population of vervets lack their main predator. This 'quasi-experimental' situation provides a unique opportunity to study the adaptability of vervet vocal production and perception in response to an ecological shift in predation risk. What happens to the vocal repertoire of this primate species in the absence of one of its vocal signal targets? Is the alarm call traditionally associated with leopards absent in these populations, or is it flexibly produced and interpreted accordingly upon perception of other threats? Furthermore, will vervet communication change as leopards are reintroduced to the area, and how will this impact other species in the park, such as baboons (Papio ursinus/cynocephalus), which would normally make use of the vervet alarm calls to predict threats? In 2019, after undertaking the necessary arrangements and refining my research methods, I will head to Gorongosa, and, through observation of the vervet monkeys, seek to answer these questions. In doing so, I will shed light on the flexibility of vervet monkey alarm call production and perception, and primate vocal communication more broadly, which in turn will inform models of the origin and evolution of human language. Vervet monkey troops exposed to various levels of predation will be selected and compared for several months over the course of the planned leopard reintroductions. Vocalisations and subsequent responses (of vervets and neighbouring baboons) will be recorded through focal follows and ad libitum sampling techniques, whilst detailed information will be collected on the context of the calls, including the presence of predators, the number of other conspecifics visible, and the demographic factors of the signaller. By adopting these fieldwork methods, I shall gain all the necessary information to conduct analysis of the collected data and establish answers to my research questions, irrespective of the scale of the reintroductions.As well as directly contributing to the study of primate communication and the origin of human language, the project will be conducted in close collaboration with the leopard reintroduction programme, leading to increased focus on the restoration of the park, and benefitting the ongoing conservation projects; as well as providing opportunities for the local community, and expanding our knowledge of the very much understudied vervets of Gorongosa through behavioural observations and census taking.