Obligatory post:

Coupled with the observation in 1975 of cannibalistic infanticide by a high-ranking female in the community, the violence of the Gombe war first revealed to Goodall the "dark side" of chimpanzee behavior. She was profoundly disturbed by this revelation; in her memoir Through a Window: My Thirty Years with the Chimpanzees of Gombe, she wrote:

For several years I struggled to come to terms with this new knowledge. Often when I woke in the night, horrific pictures sprang unbidden to my mind—Satan [one of the apes], cupping his hand below Sniff's chin to drink the blood that welled from a great wound on his face; old Rodolf, usually so benign, standing upright to hurl a four-pound rock at Godi's prostrate body; Jomeo tearing a strip of skin from Dé's thigh; Figan, charging and hitting, again and again, the stricken, quivering body of Goliath, one of his childhood heroes. ...