mound, she watched him repeatedly place stalks of grass into termite holes, then remove them from the hole covered with clinging termites, effectively "fishing" for termites. The chimpanzees would also take twigs from trees and strip off the leaves to make the twig more effective, a form of object modification that is the rudimentary beginnings of toolmaking. Humans had long distinguished themselves from the rest of the animal kingdom as "Man the Toolmaker". In response to Goodall's revolutionary findings, Louis Leakey wrote, "We must now redefine man, redefine tool, or accept chimpanzees as human!" In contrast to the peaceful and affectionate behaviours she observed, Goodall also found an aggressive side of chimpanzee nature at Gombe Stream. She discovered that chimpanzees will systematically hunt and eat smaller primates such as colobus monkeys. Goodall watched a hunting group isolate a colobus monkey high in a tree and block all possible exits; then one chimpanzee climbed up and captured and killed the colobus. The others then each took parts of the carcass, sharing with other members of the troop in response to begging behaviours. The chimpanzees at Gombe kill and eat as much as one-third of the colobus population in the park each year. This alone was a major scientific find that challenged previous conceptions of chimpanzee diet and behaviour. Goodall also observed the tendency for aggression and violence within chimpanzee troops. Goodall observed dominant females deliberately killing the young of other females in the troop to maintain their dominance, sometimes going as far as cannibalism. She says of this revelation, "During the first ten years of the study I had believed […] that the Gombe chimpanzees were, for the most part, rather nicer than human beings. […] Then suddenly we found that chimpanzees could be brutal—that they, like us, had a darker side to their nature." She described the 1974–1978 Gombe Chimpanzee War in her 1990 memoir, Through a Window: My Thirty Years with the Chimpanzees of Gombe. Her findings revolutionised contemporary knowledge of chimpanzee behaviour and were further evidence of the social similarities between humans and chimpanzees, albeit in a much darker manner. Goodall also set herself apart from the traditional conventions of the time by naming the animals in her studies of primates instead of assigning each a number. Numbering was a nearly universal practice at the time and was thought to be important in the removal of oneself from