The members of M-group don't always gather in one big gang, but they recognize one another's voices. Obsessive pant-grunting (the soft call chimps use to show submission) and pant-hooting (rapid screams broken by sharp intakes of breath conveying excitement) are the chimpanzee equivalent of IM-ing, indicating to both chimps and researchers who is hanging out with whom, and who's up and who's down on the social ladder. We hear their pant-hoots before we see the three male chimps—bigger than any I have ever seen in captivity, with barrel chests and massive arms and thighs—knuckle-running down the path. Pimu, the twenty-one-year-old alpha male, is trailed by Primus, the number three, and Orion, whom Kabeth recognizes by the white scar on his glossy black back.

When we catch up, Primus is grooming Pimu under Saba florida vines. As Pimu lies on his side, Primus makes smooching noises, using his fingers to delicately move Pimu's scrotum and planting a smacker right on his backside. Orion and two more males, Christmas and Kalunde, arrive to join in the ass kissing.

"There is a king, a prime minister, and a first lady," Kabeth whispers behind his surgical mask. In his telling, M-group behavior seems less natural science than a tale from Sophocles or some dark Shakespearean plot. Pimu, who took over as alpha male in October, is inexperienced, restless, and perhaps a little mad; two years ago, he began beating and raping his mother, a behavior as deviant for chimps as it is for humans. Kalunde, a former alpha now forty-seven years old, is physically shrunken but exerts power through others. He tried to keep Pimu's immediate predecessor in power by inviting an exiled ally to rejoin the community. The coalition failed and Pimu came out on top, but he may not last long because M-group females, who, unlike males, are free to join another group, fear and apparently loathe him.

Pimu screams and comes charging down the path where we are standing. Kabeth grabs us all in a protective bear hug, and we stand in a vertical cluster as Pimu brushes past us on two legs, arms raised over his head. Mahale chimps sometimes shove humans off trails but have never harmed an observer. By contrast, one of Jane Goodall's famous subjects, a male named Frodo, nearly broke her neck, and in 2002 killed and partially ate the fourteen-month-old daughter of a park employee. Some scientists say that when human civilization encroaches on chimp territory, it becomes natural for chimps, which hunt monkeys, to view small children as food. Kabeth says Pimu was reacting to an unseen chimp's pant-hoot, not to our presence. We are unscathed, although in the excitement I've stood on a nest of siafu ants; I now have ants in my pants, and some are attacking me with their pincers.

In Batongwe mythology, Kabeth says, chimps are ancestors who turned their back on village life, choosing instead to wander the forest. In this narrative of a reverse Eden, chimps refuse to speak with humans lest they be put to work. The story turns poignant when Kabeth tells us how his own Batongwe family was forced to leave the forest in 1974 when he was four years old.