Seasonal reproduction is common in mammals. Whereas specific conditions triggering a seasonal response can only be identified in controlled experiments, large-scale comparisons of reproduction in natural habitats and zoos can advance knowledge for taxa unavailable for experimentation. We outline how such a comparison can identify species whose seasonal physiology is linked to photoperiodic triggers, and those whose perceived seasonality in the wild is the consequence of fluctuating resources without a photoperiodic trigger. This concept groups species into those that do not change their aseasonal pattern between natural habitats and zoos because they are not constrained by resources in the wild, those that do not change a seasonal pattern between natural habitats and zoos because they are triggered by photoperiod irrespective of resources, and those that change from a more seasonal pattern in the natural habitat to an aseasonal pattern in zoos because the zoo environment alleviates resource limitations experienced in the wild. We explain how detailed comparisons of mating season timing in both environments can provide clues whether a specific daylength or a specific number of days after an equinox or solstice is the likely phototrigger for a taxon. We outline relationships between life history strategies and seasonality, with special focus on relative shortening of gestation periods in more seasonal mammals. Irrespective of whether such shortening results from the adaptive value of fitting a reproductive cycle within one seasonal cycle (minimizing ‘lost opportunity’), or from benefits deriving from separating birth and mating (to optimize resource use, or to reduce infanticide), reproductive seasonality may emerge as a relevant driver of life history acceleration. Comparisons of data from natural habitats and zoos will facilitate testing some of the resulting hypotheses.

中文翻译：

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哺乳动物季节性繁殖的基本考虑，包括通过比较自然栖息地和动物园进行测试

季节性繁殖在哺乳动物中很常见。而触发季节性反应的特定条件只能在受控实验中确定，而对自然栖息地和动物园中的繁殖进行大规模比较可以提高对无法进行实验的分类群的了解。我们概述了这种比较如何识别季节性生理与光周期触发相关的物种，以及那些在野外感知季节性​​是由于没有光周期触发而波动的资源的结果的物种。这个概念将物种分为自然栖息地和动物园之间不改变其季节性模式的物种，因为它们不受野外资源的约束，那些不改变自然栖息地和动物园之间的季节性模式的物种，因为它们不受光周期的影响资源，以及那些从自然栖息地中更具季节性的模式转变为动物园中的非季节性模式的那些，因为动物园环境减轻了野外经历的资源限制。我们解释了两种环境中交配季节时间的详细比较如何提供线索，即特定日长或昼夜平分点或冬至后的特定天数是否可能是分类群的光触发因素。我们概述了生活史策略与季节性之间的关系，特别关注更多季节性哺乳动物妊娠期的相对缩短。无论这种缩短是由于在一个季节周期内拟合生殖周期的适应性价值（最大限度地减少“失去的机会”），还是由于分离生育和交配（优化资源利用，或减少杀婴）带来的好处，生殖季节性可能会成为生命史加速的相关驱动因素。比较来自自然栖息地和动物园的数据将有助于检验一些由此产生的假设。