Hunting of mammals by central chimpanzees (Pan troglodytes troglodytes) in the Loango National Park, Gabon

Abstract

The predation and consumption of animals are common behaviours in chimpanzees across tropical Africa. To date, however, relatively little is known concerning the hunting behaviour of central chimpanzees (Pan troglodytes troglodytes). Here, we provide the first direct observations of hunting behaviour by individuals of the newly habituated Rekambo community in the Loango National Park, Gabon. Over a period of 23 months (May 2017 to March 2019), we observed a total of 61 predation attempts on eight mammal species, including four monkey species. The two most frequently hunted species were two monkey species (Cercocebus torquatus,Cercopithecus nictitans), which are not hunted at other long-term field sites. The majority of predation events observed involved parties of an average of eight individuals, mainly adult males, with hunting success being higher with increasing numbers of participants. Hunting occurred all year round, but hunting rates increased in the dry season, the period of high fruit availability in the Loango National Park. These results are in line with the nutrient surplus hypothesis which explains seasonal variation in hunting behaviour in several populations of eastern chimpanzees (Pan troglodytes schweinfurthii: e.g., Mahale, Tanzania; Ngogo, Uganda). Finally, with a hunting frequency of 2.65 hunts per month, the Rekambo community had higher hunting rates than other sites (Bossou, Republic of Guinea; Kahuzi-Biega, Democratic Republic of Congo; Budongo, Uganda) where red colobus monkeys are also absent. We discuss these results and compare them to patterns at other long-term sites.

Lethal coalitionary attacks of chimpanzees (Pan troglodytes troglodytes) on gorillas (Gorilla gorilla gorilla) in the wild

“…Across study communities, the degree of dietary overlap ranges between: 50% Kahuzi-Biega; Gorilla beringei graueri, Pan troglodytes schweinfurthii 75 and 60-80% Loango, Lopé, and Ndoki; Gorilla g. gorilla, Pan t. troglodytes 66,74,76 . The two lethal encounters we observed occurred at times characterized by food scarcity and a period of high dietary overlap (for fruit resources) 45,74 -February and December 2019. In contrast, the two previously observed peaceful co-feeding events took place in April, a month characterized by relatively low dietary overlap between the two species 45,74 .…”

“…The two lethal encounters we observed occurred at times characterized by food scarcity and a period of high dietary overlap (for fruit resources) 45,74 -February and December 2019. In contrast, the two previously observed peaceful co-feeding events took place in April, a month characterized by relatively low dietary overlap between the two species 45,74 .…”

“…Although differences in behaviours accompanying hunting and hunting patrol patterns have been observed across sites, the behaviors observed at Loango were similar to the patterns reported for Taï 41,60 and Ngogo 38 . For instance, the chimpanzees showed conspicuous behaviours prior to hunting such as being extremely attentive to any arboreal movements, scanning, changing directions several times without vocalizing, and performing specific call types-hunting calls 38,45 . Post-hunting behaviour is characterized by the prevalence of high-ranking males as the primary prey possessors and consumers, high levels of attention, arousal and excitement of party members, as well as begging and food www.nature.com/scientificreports/ sharing 13,[40][41]61 .…”

“…As in the lethal interactions discussed here, carnivores tend to attack their closest dietary competitors 31 , most agonistic encounters occur in seasonal environments when food is scarce 27 , and killings decrease abruptly when dietary overlap is reduced 73 . Gorillas and chimpanzees show considerable dietary overlap and have a relatively high potential for dietary competition 45 , 74 . Across study communities, the degree of dietary overlap ranges between: 50% Kahuzi-Biega; Gorilla beringei graueri, Pan troglodytes schweinfurthii 75 and 60–80% Loango, Lopé, and Ndoki; Gorilla g. gorilla, Pan t. troglodytes 66 , 74 , 76 .…”

“…Although hunting is often opportunistic 37 , chimpanzees at Taï, Taï National Park, Cote D'Ivoire 41 and Ngogo, Kibale National Park, Uganda 38,42 have been observed to search actively for prey and listen for distinct vocalizations. Chimpanzees prey upon a broad variety of taxa including birds, insects, non-primate mammals, monkeys, and reptiles e.g., 13,[40][41][42][43] , with prey preferences differing between chimpanzee populations based on local availability 37,44,45 .…”