Talk abstract: As the human lineage evolved over the course of the past 3-4 million years the guild of large carnivores lost more than 2/3 of its number of species, an even greater amount of its ecological diversity. Are these evolutionary trajectories causally linked? In this talk I will explore some of the evidence that speaks to this question, including measures of diversity and disparity, as well as the role of competition within the carnivore guild.