Patrolling Territorial Boundaries
A major goal of the Figan Follow was to track the alpha male’s travel to territorial boundaries where he might encounter chimps from neighboring communities — Kahama to the south and Mitumba to the north.
Figan’s core area spanned three valleys: Kakombe, Kasakela, and occasionally Linda (see map, below). Small groups of Kasakela chimps including Figan made three incursions to the north (Days 1, 32, and 49), and even crossed the Rutanga stream on Day 32. They also made three incursions to the south (Days, 38, 42, and 45) including one foray deep into Kahama territory where they heard squeaks from a nearby chimp. Their search for this chimp was unsccessful (photos below).
During these incursions, the group sometimes exhibited “patrolling behaviors,” in which they move silently in a tight formation and pause often to listen and look for signs of rivals, such as fresh feces or nests. These incursions typically ended with wild sessions of pant-hooting and displaying when returning to relative safety, a behavior pattern described as “tension release.”
This map shows Figan’s location “on-the-hour” (orange dots, n=563) during daylight hours (not in a nest) over the fifty days. 
Incursion into Kahama on Day 38
The day began peacefully as Faben led travel along the beach from Kakombe to Mkenke. The group consisted of adult males Figan, Faben, Satan, Jomeo, and Sherry, adolescent male Goblin, and adult females Gigi and Fifi (and her young son Freud).
The group traveled up the “watu” (people) path separating Mkenke from Kahama valleys. The local people use this path occasionally to walk between the fishing huts on the lake and their villages on the other side of the Rift. Upon reaching a good vantage point, the chimps sat on the path in a compact group, quietly looking out northward over lower Mkenke Valley — watching and listening (photo).
After 15 minutes, the group traveled farther up the path to the ridge separating Mkenke and Kahama. There they climbed into a small, exposed tree on the hillside looking down into Busambo, a small ravine to the south. They sat quietly, constantly listening and watching (photo). After forty minutes, Sherry and Jomeo led the group on a steathful advance to the next ravine — Bare-tree Korongo — where they took a position in a semi-exposed tree.
Faben (left), Jomeo (center), and Gigi (right) look down into the Busambo ravine. Young Freud (below) also watches.
Soon thereafter, a Kahama chimp squeaked from less than 200 yards away, possibly upon seeing this group of marauders. The vocalization caused a panic of excitement, as the Kasakela chimps silently hugged one another, grinned, and put their hair out. They then stalked in that direction (photo), looking into the trees and stopping often to sniff the ground and branches. Their search turned up empty. The chimp who had made the squeaks had dodged a bullet. Upon returning to Mkenke, Figan and his gang erupted into wild celebratory displays of hooting, drumming, and branch-shaking .
In single file are Sherry, Figan, Satan, and Gigi. To the left is Jomeo inspecting a tree trunk; to the right (partially hidden) are Faben and Goblin. Petro Leo observes from the upper left.
Incursion into Rutanga on Day 32
A group consisting of Figan, Faben, Satan, Goblin, Patti, and Fifi (plus young Freud) traveled to the ridge separating Linda and Rutanga valleys. Their pant-hoots upon arrival met with no reply, suggesting that Mitumba chimps were not in the vicinity.
Faben rests in an mnazi tree overlooking Rutanga valley.
After 40 minutes of resting, Satan led the group down to the Rutanga stream. Figan drank from the stream and ate leaves for a while before Satan led travel back to the area where they had been resting.
Fifi rests near Faben.
Patti started screaming from down by the stream, possibly having lost contact with the group. Figan and the others responded with pant-hoots from back up near the mnazi trees. (Thirty-one years later, Mitumba chimps attacked and killed Patti.)
Although the group had exhibited caution while entering Rutanga, this was not a bonafide patrol like what happened on Day 38.
Goblin joins the slumber party.