New research finds that 500 years of over-exploitation has halved mammal populations in South America's once majestic Atlantic Forest. A new analysis of mammal populations reveals the devastating effects of human disturbance since the area was first colonized in the 1500s. They found that apex predators and large carnivores, such as jaguars and pumas, as well as large-bodied herbivores, such as tapirs, were among the groups whose numbers had suffered the most.