I knew Chimpanzees had been observed using some rudimentary tools but this piece by Mary Roach for National Geographic is crazy:
In 2007 Jill Pruetz, an anthropologist at Iowa State University, reported that a Fongoli female chimp named Tumbo was seen two years earlier, less than a mile from where we are right now, sharpening a branch with her teeth and wielding it like a spear. She used it to stab at a bush baby—a pocket-size, tree-dwelling nocturnal primate that springs from branch to branch like a grasshopper. Until that report, the regular making of tools for hunting and killing mammals had been considered uniquely human behavior. Over a span of 17 days at the start of the 2006 rainy season, Pruetz saw the chimps hunt bush babies 13 times. There were 18 sightings in 2007. It would appear the chimps are getting creative.