In polygynous and polygynandrous species, there is often intense male-male competition over access to females, high male reproductive skew, and more male investment in mating effort than parenting effort [1]. However, the benefits derived from mating effort and parenting effort may change over the course of males' lives. In many mammalian species, there is a ∩-shaped relationship between age, condition, and resource holding power as middle-aged males that are in prime physical condition outcompete older males [2-8] and sire more infants [9-12]. Thus, males might derive more benefits from parenting effort than mating effort as they age and their competitive abilities decline [13]. Alternatively, older males may invest more effort in making themselves attractive to females as mates [14]. One way that older males might do so is by developing relationships with females and providing care for their offspring [14, 15]. Savannah baboons provide an excellent opportunity to test these hypotheses. They form stable multi-male, multi-female groups, and males compete for high ranking positions. In yellow and chacma baboons (Papio cynocephalus and P. ursinus), there is a ∩-shaped relationship between male age and dominance rank [12], and high rank enhances paternity success [12, 16]. Lactating female baboons form close ties ("primary associations" hereafter) with particular males [15-20], who support them and their infants in conflicts [15, 19] and buffer their infants from rough handling [20]. Females' primary associates are often, but not always, the sires of their current infants [16, 20-22].

中文翻译：

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一夫多妻哺乳动物整个生命过程中雄性生殖策略的变化。

在一夫多妻和一夫多妻的物种中，雄性通常会在获取雌性方面存在激烈的竞争，雄性生殖偏度高，而且雄性在交配方面的投入多于育儿努力[1]。然而，交配努力和育儿努力所带来的好处可能会随着雄性的一生而改变。在许多哺乳动物物种中，年龄、身体状况和资源保持力之间存在 ∩ 型关系，因为身体状况良好的中年雄性胜过年长雄性 [2-8] 并生育更多的婴儿 [9-12]。因此，随着年龄的增长和竞争能力的下降，雄性可能从育儿努力中获得比交配努力更多的好处[13]。或者，年长的雄性可能会投入更多的精力来吸引雌性作为配偶 [14]。老年男性可能这样做的一种方式是与女性发展关系并照顾他们的后代 [14, 15]。萨凡纳狒狒提供了检验这些假设的绝佳机会。他们形成稳定的多男多女群体，男性争夺高位。在黄色和 chacma 狒狒（Papio cynocephalus 和 P. ursinus）中，雄性年龄与优势等级之间存在 ∩ 型关系 [12]，高等级提高了亲子关系的成功率 [12, 16]。哺乳期的雌性狒狒与特定的雄性 [15-20] 形成密切的联系（以下称为“主要联系”），它们在冲突中支持它们和它们的婴儿 [15, 19] 并保护它们的婴儿免受粗暴对待 [20]。雌性的主要伙伴通常（但并非总是）是其当前婴儿的父亲 [16, 20-22]。