Table 2.

Reports of interspecific association between sympatric chimpanzees and gorillas

Ape Taxa, Study Site Location	Period	Interspecific Interactions
		Foraging	Spatial Intersection	Agonism	Not Known
G. g. gorilla, P. t. troglodytes
Goualougo, Rep. Congoa	1999–2020	148	117		20
Mondika, Rep. Congob	1999–2020	+
Ndoki, Rep. Congoc	1989–1992	4	2
Rio Muni, Equat. Guinead	1966–1968	–	1
Lope, Gabone	1984–1993	?
Loango, Gabonf	2005–2019	2		2	7
Ndakan, C.A.R.g	1986–1990	+
G. b. beringei, P. t. schweinfurthii
Bwindi, Ugandah	1996–2005	5
Kahuzi, Dem. Congoi	1994–2002	3	7

Foraging includes both cofeeding and feeding in proximity. Spatial intersection included chimpanzees and gorillas being observed within 50m of each other, but with no apparent interaction. At Loango, two particular interactions between chimpanzees and gorillas involved lethal aggression and so were categorized as agonism. Social interactions among sympatric apes in Goualougo were observed in various contexts.

+ observed, but number of occurrences not available; – not observed; ? information not available.

^aThis study.

^bMorgan, pers comm.

^cKuroda, 1992, Nishihara, 1992, Kuroda et al., 1996.

^dJones and Sabater Pi, 1971.

^eTutin and Fernandez, 1985, Tutin and Fernandez, 1993.

^fHead et al., 2011, Southern et al., 2021.

^gFay, personal comm.

^hStanford and Nkurunungi, 2003.

ⁱYamagiwa et al., 1996a, 1996b, Basabose and Yamagiwa, 2002, Yamagiwa and Basabose, 2006, Yamagiwa and Basabose, 2009.