It is two decades since Sir David looked at the "Life of Mammals." In that time the issues facing mammals have grown and grown – today, less than 6% of the world's mammal biomass is made up of wild mammals, and many face extinction. As well as bringing a fresh understanding of this remarkable group of animals we highlight many of the problems faced by mammals in a rapidly changing world. To do this, we explore how mammals are coping living alongside perhaps the most successful mammal of all – us, revealing both winners and losers in today's new wild.