Fifty years ago today, Jane Goodall arrived at Gombe Stream Chimpanzee Reserve (now Gombe National Park) in Tanzania and began documenting the lives of the chimpanzees that lived there. When Goodall ended her fieldwork to advocate for the chimps and the environment in general, other researchers took up the work, and the Gombe chimp research project is now one of the longest running studies of a population of wild animals. Since the study's start in 1960, researchers have published more than 200 scientific papers about the chimps, including some of the most important discoveries about our primate cousins. Here are the top five:

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1) Chimpanzees eat meat: Before Goodall began her studies in Gombe, most scientists thought that chimpanzees were vegetarians. That notion was quickly dropped after Goodall observed chimps eating what appeared to be a freshly killed piglet in October 1960. She would later observe chimps hunting young bush pigs and baby colobus monkeys.

2) Chimpanzees use tools: Goodall observed two chimps, David Greybeard and Goliath, using sticks to extract termites, the first instance of a non-human species using a tool. Gombe chimps also use sticks to catch army ants and use leaves to soak up water to drink and to clean themselves. Other chimps have been observed using stones to crack open nuts.

3) Chimpanzees engage in warfare: In 1974, the Gombe chimps split into two groups that then proceeded to battle for dominance for the next four years. This was the first instance of a non-human primate species engaging in long-term war.

4) Chimpanzees can be cannibals: In 1975, one female chimp, Passion, was observed killing another's infant and sharing the meat with her daughter, Pom. The pair would continue their infant cannibalism for two years. A similar event has been observed among chimps in Uganda.

5) Chimpanzees have complex social relationships: Chimpanzees live in small groups of up to six individuals, and several of these smaller groups belong to a larger community of 40 to 60 chimps. The males, led by an alpha, dominate the group, while the females have their own hierarchy. Within those groups, there is a complex set of social interactions, a chimp "soap opera" almost, that has kept the Gombe researchers busy for the past five decades.