Chimpanzee
Jane Goodall discovered that chimps hunt and eat smaller primates such as Colobus monkeys. Goodall watched a hunting group isolate a monkey high in a tree, block all possible exits. Then one chimpanzee climbed up and captured and killed the monkey. The others then each took parts of the carcass, sharing with other members of the troop in response to begging behaviours. The chimps at Gombe kill and eat as much as one-third of the Colobus population in the park each year. This was a major scientific discovery: it challenged previous ideas of chimp diet and behavior.