Parents in many animal species provide care to their offspring as a mechanism to enhance their own fitness. In mammals, this behavior is expressed mostly by the females, but also by males of some species. Proximally, rates of paternal offspring care have been linked to organizational and activational effects of testosterone. Specifically, intrauterine position of male fetuses is associated with differential exposure to testosterone, leading to development of males with different levels of masculinization (assessed through differences in the length of the anogenital distance (AGD). The relative roles played by organizational and activational effects of testosterone on male parental care remain unclear. In this study, we aimed to determine if male sex-biased uterine environment and testosterone levels across the breeding period explain variation in paternal care in the social rodent, Octodon degus. Neither quantity (time with the offspring) nor quality (frequency of grooming and retrieving) of paternal care was affected by male sex-biased uterine environment, nor did paternal care significantly differ across the different stages of male reproduction. In contrast, paternal care was associated with maternal care. Quantity of male care decreased with increasing quantity of maternal care, and quality of male care increased with increasing quality of maternal care. While serum testosterone did not differ between males with different sex-biased uterine environment, male testosterone tended to increase during mating and decrease when pregnant females or offspring were present.

许多动物物种的父母都会照顾他们的后代，以此作为增强自身健康的机制。在哺乳动物中，这种行为主要由雌性表达，但也由某些物种的雄性表达。最近，父系后代的照顾率与睾酮的组织和激活作用有关。具体而言，男性胎儿的宫内位置与睾酮暴露的差异有关，导致男性发育不同程度的男性化（通过肛门生殖器距离 (AGD) 的长度差异进行评估）。组织和激活效应所起的相对作用睾酮对男性父母的照顾尚不清楚。在这项研究中，八齿象。父亲照顾的数量（与后代在一起的时间）和质量（梳理和取回的频率）都不受男性性别偏见子宫环境的影响，在男性生殖的不同阶段，父亲的照顾也没有显着差异。相比之下，父亲的照顾与母亲的照顾有关。男性护理的数量随着产妇护理数量的增加而减少，而男性护理的质量随着产妇护理质量的提高而提高。虽然具有不同性别偏向子宫环境的雄性之间的血清睾酮没有差异，但雄性睾酮在交配期间趋于增加，而在怀孕的雌性或后代存在时则趋于减少。