Data from: Sexual selection on skeletal shape in Carnivora

Lifetime reproductive success of males is often dependent upon the ability to physically compete for mates. However, species variation in social structure leads to differences in the relative importance of intraspecific aggression. Here we present a large comparative data set on sexual dimorphism in skeletal shape in Carnivora to test the hypotheses that carnivorans exhibit sexual dimorphism in skeletal anatomy that is reflective of greater specialization for physical aggression in males relative to females and that this dimorphism is associated with the intensity of sexual selection. We tested these hypotheses using a set of functional indices predicted to improve aggressive performance. Our results indicate that skeletal shape dimorphism is widespread within our sample. Functional traits thought to enhance aggressive performance are more pronounced in males. Phylogenetic model selection suggests that the evolution of this dimorphism is driven by sexual selection, with the best-fitting model indicating greater dimorphism in polygynous versus non-polygynous species. Skeletal shape dimorphism is correlated with body size dimorphism, a common indicator of the intensity of male-male competition, but not with mean body size. These results represent the first evidence of sexual dimorphism in the primary locomotor system of a large sample of mammals.

雄性个体的终生繁殖成功率，通常取决于其通过身体竞争获取配偶的能力。然而，不同物种的社会结构存在差异，这使得种内攻击（intraspecific aggression）的相对重要性各不相同。本文呈现了一组针对食肉目（Carnivora）骨骼形态性二态性（sexual dimorphism）的大型比较数据集，用以检验两项假说：其一，食肉目动物的骨骼解剖结构存在性二态性，且相较于雌性，雄性在针对身体攻击的特化方面表现更显著；其二，该性二态性与性选择（sexual selection）的强度相关联。我们通过一组旨在提升攻击性能的功能指标对上述假说进行了检验。研究结果表明，骨骼形态性二态性在我们的样本中广泛存在。被认为可增强攻击性能的功能性状，在雄性个体中表现得更为突出。系统发育模型选择分析显示，该性二态性的演化由性选择驱动，最优拟合模型表明，一雄多雌制物种的性二态性程度高于非一雄多雌制物种。骨骼形态性二态性与体型二态性——雄性间竞争强度的常见指示指标——存在相关性，但与平均体型并无关联。本研究结果首次证实了大型哺乳动物样本中，其主要运动系统存在性二态性。