Dr. Mauro Galetti is a Brazilian biologist interested in examining the effects of defaunation in ecological and evolutionary processes. Here he show how over-abundant ungulates (collared peccaries) is the other side of the coin in La Selva, Costa Rica. A forest with too many mammals is also bad. While spider monkeys are dispersing Virola seeds, peccaries prey upon seeds. This is a natural phenomena, but when a forest lack top predators (jaguars and pumas), their preys increase in abundance, and changes the balance of seed dispersal and seed predation.