I want to understand how explaining the evolution of mammalian breeding seasonality makes it possible to anticipate their response to climate change and how it can be used to improve public policies. I have therefor developed two approaches. The first one is a large-scale comparative analysis that will provide a global view of the seasonality of mammalian reproduction and its evolutionary determinants, including social and life history determinants. The second approach is a theoretical study using a simulation model of optimization. Based on physiological and energy parameters, this model retraces the reproductive cycles of several species (baboons and wild boar) in order to test the influence of ecology and life history on reproductive seasonality.