I read this in Temple Grandin's new (and often quite interesting) Animals Make Us Human: Creating the Best Life for Animals:
She [Jane Pruetz] spent four years just habituating the chimpanzees to her presence before she could study them. Then she spent three summers observing their lives. She discovered that some of the chimpanzees make spears out of tree branches and use them to spear bush babies inside hollow trees. Bush babies are small furry animals. The chimpanzee breaks a branch off the tree, strips off the leaves, and sharpens one end to a point with its teeth. Then it stabs the spear violently inside the hollowed trunk to kill any bush baby that might be inside. This discovery is so revolutionary that it has caused a big controversy in the field of primate research, because it is the first documentation of an animal using a tool as a weapon for hunting.
But alas we are told:
Animal research is getting more and more what I call "abstractified." Instead of people studying the real animals in their natural habitats, researchers use fancy statistical software to construct statistical models, and then they study the models.