22 UKRI-SBE: Primate natal coats: Form and function

在许多灵长类物种中，婴儿的颜色与成体和背景颜色形成鲜明对比。这是违反直觉的--为什么要让一个群体中最脆弱的成员受到威胁？这个项目将调查灵长类动物中婴儿颜色的形式和功能，让人们深入了解婴儿在灵长类动物社会制度中的角色--我们的直接进化血统。关于婴儿显眼的功能，已经提出了许多想法，但并没有进行严格的研究。这些措施包括颜色警告可能杀婴的外群体雄性或捕食者，婴儿将受到群体的保护，混淆婴儿的父亲身份以防止杀婴，帮助照顾者跟踪婴儿，以及促进母亲和非母亲对婴儿的照顾。这个项目将通过客观测量来自许多灵长类物种的许多个体在整个婴儿期的颜色，对不同物种的婴儿颜色进行比较分析，以及行为实验来检验这些多重假设，以找出母亲、父亲和非父亲对不同颜色的婴儿的反应。颜色将在全球动物园、保护区和研究中心使用校准和标准化的数码摄影进行测量，当地研究人员将在整个发育期间拍摄婴儿的照片。然后将使用依赖视觉系统的方法对这些数据进行处理，以获得灵长类婴儿外表的“接收器-眼睛”。对灵长类物种的比较分析将检验每个功能性假说做出的预测，即婴儿的颜色应该如何与物种的行为、生态和社会制度相关。例如，父权混淆假说将预测，在亲子关系确定性较低的物种中，婴儿应该更引人注目。功能的实验测试包括展示多种圈养灵长类动物的图像，这些图像已经被操纵成不同的婴儿和青少年的颜色，并测量不同接受者对不同操纵的兴趣。各种假说对谁应该对什么图像特性感兴趣做出了独特的预测，首次用强有力的实验测试了灵长类婴儿显眼的功能。

The color of infants in many primate species contrasts starkly with adult and background color. This is counterintuitive - why make the most vulnerable members of a group conspicuous to threats? This project will investigate the form, and function of infant coloration in primates, giving insight into the role of infants in the social systems of primates - our direct evolutionary lineage. Many ideas for the function of infant conspicuousness have been proposed but not rigorously investigated. These include the color warning potentially infanticidal out-group males or predators that the infant will be defended by the group, confusing the paternity of infants to prevent infanticide, helping caregivers keep track of the infant, and facilitating the care of infants by mothers and non-mothers. This project will test these multiple hypotheses by objectively measuring the color of many individuals from many primate species throughout infancy, conducting comparative analyses of infant coloration across species, and behavioral experiments to find out how mothers, fathers and non-fathers respond to different colored infants. Color will be measured using calibrated and standardized digital photography at zoos, sanctuaries and research centers globally, with local researchers taking photos of infants throughout the period of development. These will then be processed using visual-system dependent methods to get a 'receiver-eye-view' of primate infant appearance. Comparative analyses across primate species will test the predictions made by each of the functional hypotheses about how infant color should relate to species' behavior, ecology and social system. For example, the paternity confusion hypothesis would predict that infants should be more conspicuous in species where paternity certainty is low. The experimental tests of function involve showing multiple species of captive primate images that have been manipulated to different infant and juvenile colors and measuring the interest of different receivers to different manipulations. The various hypotheses make unique predictions about who should be interested in what image properties, testing the function of primate infant conspicuousness with powerful experiments for the first time.