Competition between baboons and chimpanzees at Mahale

Abstract

It appears that the yellow baboons of Kasoje have recently increased in number and expanded their ranges enormously at the cost of the M group chimpanzee range (1, 2). The question of why they have expanded their ranges is addressed here. Before the national park was established, there were only two baboon troops at Kasoje, one in the southern region and the other in the northern region. The northern troop's range, which S. Uehara and I had studied in 1973-74, was very narrow and limited to the open areas along the shoreline of Lake Tanganyika (Fig. 1) (3). Kasiha Village was at the northern limit of the troop range, and since villagers were antagonistic to crop-raiders, baboons did not penetrate more deeply into the Kasoje area at that time. Figure 1 Expansion of the range use by baboons 1974-2002 (Estimate)