Jean-François Lemaître is a Research Director at the French National Centre for Scientific Research (CNRS) based at the Claude Bernard Lyon 1 University. He is an evolutionary biologist who studies ageing in wild mammals through a multidisciplinary approach combing evolutionary demography, ecology and ecophysiology. His research currently focuses on identifying factors shaping the diversity of reproductive ageing patterns observed across mammal species; females and males. Samuel Pavard is a Professor of Eco-anthropology at the National Museum of Natural History in Paris. He is a demographer with broad interests in understanding the biological, environmental, cultural and social determinants of ageing and longevity in humans and, in particular, investigating the joint evolution of actuarial and reproductive senescence with cognitive and social capabilities in our species. His is currently investigates the role played by evolutionary trade-offs between mortality components in shaping mortality at old ages, in mammals in general and in humans in particular.