Sex drives intraspecific scaling of home range size in mammals

Animal home range sizes (HR) are fundamental ecological measures, encompassing the area necessary for an organism to obtain food and nonfood resources needed for survival and reproduction. Understanding variation in HR provides important insights into underlying ecological processes driving space use, contributing to species management and conservation. HR is widely known to increase allometrically at an interspecific level. However, it remains unclear whether the interspecific allometric scaling of mammals’ HR can also be consistently observed within species. Additionally, the influence of sex-specific metabolic and behavioral patterns on intraspecific variation in both HR and HR scaling is not well understood. To address this knowledge gap, we GPS-tracked 475 individuals across Brazil, encompassing 18 mammal species. We estimated individuals’ HR and modeled intraspecific variation in HR against body mass and sex, while controlling for habitat quality and phylogenetic relationships. Males used larger areas and displayed steeper HR scaling than females. While males showed a positive allometric scaling similar to interspecific findings reported in the literature (exponent = 1.23), females’ body mass had no statistically discernible effect on HR. Our findings suggest that sex-related metabolic and behavioral traits influence space use across mammals. In general, males have greater energetic and evolutionary incentives to expand their HR with increasing BM, as well as more physical capacity to do so, compared to females. We highlight that traditional studies on HR and, especially, HR scaling that disregard individual sex may, in reality, reflect an average of two distinct patterns, while failing to accurately represent either one.

动物家域大小（Home Range, HR）是基础生态学指标，指生物获取生存与繁殖所需食物及非食物资源的必要区域。理解HR的变异规律有助于揭示驱动空间利用的潜在生态过程，为物种管理与保护提供重要参考。HR在种间水平上呈异速增长是广为人知的现象。然而，哺乳动物HR的种间异速尺度关系是否也能在种内一致观测到，目前仍不明确。此外，性别特异性代谢与行为模式对HR及HR尺度关系的种内变异的影响尚不明确。为填补这一知识空白，我们在巴西境内对18种哺乳动物的475个个体进行了GPS追踪。我们估算了个体的HR，并构建模型分析HR的种内变异与体重、性别的关系，同时控制栖息地质量与系统发育关系的影响。雄性的家域面积更大，且HR尺度关系的斜率比雌性更陡峭。雄性表现出与文献中报道的种间结果相似的正异速尺度关系（指数=1.23），而雌性的体重对HR无统计学显著影响。我们的研究结果表明，与性别相关的代谢及行为特征影响哺乳动物的空间利用。总体而言，与雌性相比，雄性随体重（Body Mass, BM）增加而扩大HR的能量及进化动机更强，且具备更强的生理能力。我们强调，传统HR研究（尤其是忽略个体性别的HR尺度关系研究）实际上可能反映的是两种不同模式的平均值，而无法准确代表其中任何一种。