Vocal correlates of mate quality and proceptivity in the vocalizations of white rhinoceros

人类声音的非语言声学提示被认为是表明配偶质量的装饰品，因此对性行为和配偶选择有重要影响。因此，声音提示包含有关发送者的身体特征、动机状态和性激素水平的信息。对非人类哺乳动物的研究发现了类似的发声关联，这表明非人类哺乳动物的发声关联也反映了性行为和配偶选择的重要近似性机制。这种发声相关性在非季节性繁育大型体型物种方面应该发挥重要作用。由于雄性和雌性经常分开生活，雌性的生殖输出很低，因此在正确的时间找到高质量的交配伙伴是很重要的。然而，关于这类物种的发声相关性的数据是有限的，因此，作为第一个基本步骤，该项目将研究发声是否与南白犀牛的性行为和配偶选择的近距离机制相关。到目前为止，犀牛缺乏与激励状态和发送者荷尔蒙水平相关的发声相关数据，而且有关身体特征的数据仅限于一种叫声类型。因此，整个项目将包括四项研究。这些研究将调查白犀牛的发声是否与(1)发送者的身体特征，(2)发送者的动机状态，(3)发送者的性激素水平存在，以及(4)同种物种是否能根据雌性或雄性的声音识别生育能力有关。因此，这些发声关联可能编码配偶的质量、交配意愿以及发送者的生殖状态，并将在性行为中发挥重要作用。将南方白犀牛的研究结果与群体生活哺乳动物或/和季节性繁殖者的研究结果结合起来，将有助于更深入地了解社会结构和/或交配策略是如何塑造声音交配行为的。因此，该项目将有助于阐明声音与哺乳动物的性行为和交配行为相关的生物学功能和原理。

Non-verbal acoustic cues of the human voice are suggested to be an ornament signaling mate quality and therefore have an important impact on sexual behavior and mate choice. Thus, acoustic cues contain information about the physical characteristic, the motivational state and the level of sex hormones of the sender. Studies in nonhuman mammals revealed similar vocal correlates suggesting that vocal correlates in nonhuman mammals reflect also important proximate mechanisms for sexual behavior and mate choice. Such vocal correlates should play an important role in non-seasonally breeding large-bodied species. Because males and females often live separated from each other and females have a low reproductive output, it is important to find a high-quality mating partner at the right time. However, data on vocal correlates on such species are limited, therefore this project will investigate, as a first essential step, whether vocal correlates as proximate mechanisms for sexual behavior and mate choice, in the Southern white rhinoceros. To date, data on vocal correlates related to the motivational state and the hormonal level of the sender are lacking in rhinoceros and data on physical characteristics are limited to only one call type. Thus, the whole project will consist of four studies. These studies will investigate whether in white rhinoceros vocal correlates related to (1) the physical characteristics of the sender, (2) the motivational state of the sender, (3) the level of sex hormones in the sender exists and whether (4) conspecifics can recognize the fertility of females or male quality based on their voices. Thereby, these vocal correlates might encode mate quality, the willingness to mate as well as the reproductive status of the sender and will play an important role in sexual behavior. Combining the results of the Southern white rhinoceros with findings in group living mammals or/and seasonal breeders will allow a deeper understanding how vocal mating behavior is shaped by social structure of and/or mating strategy. Thus, the project will help to clarify the biological function and principles of vocal correlates on sexual interactions and mating behavior in mammals.