For instance, a recent study on western lowland gorillas ( Gorilla gorilla gorilla) suggested that groups may show high levels of territoriality and actively defend core regions of their home ranges against neighbours 26. The majority of studies have, however, only focused on one eastern sub-species ( Gorilla beringei beringei), limiting an in-depth understanding of the behavioural diversity of gorillas. Unlike chimpanzees, the home ranges of neighbouring gorilla groups overlap greatly, but intergroup encounters also range from non-agonistic affiliative encounters to coalitionary agonistic interactions involving physical violence, infanticide 8– 10 and occasionally even fatal injuries 18, 23– 25 to adult males. Across their geographic range, gorillas live in cohesive social groups consisting of one or more adult males, adult females, and their offspring 8, 20– 22. Gorillas (genus Gorilla) are as genetically distant from chimpanzees (genus Pan) as they are from humans (genus Homo), and are thought to have separated from a shared ancestor around eight million years ago 19. In contrast, intraspecific killings in gorillas have almost exclusively been observed in intergroup encounters 10, 18 (but see 9). The latter has been associated with fission–fusion social systems and has spurred considerable research attention, suggesting functional parallels and evolutionary continuities between chimpanzee violence and lethal intergroup raiding in humans 6, 16, 17. During these patrols, chimpanzees travel to the periphery of the territory to search for signs of members of other communities or may even make deep incursions into neighbouring communities involving lethal coalitionary attacks 13– 15. The majority of killings involve intercommunity rather than intracommunity attacks, and most often are made by coalitions of males during territorial boundary patrols 5, 13. Rates of intraspecific killings vary considerably among chimpanzee communities, with adult males being both the main attackers and the main victims 11. However, it is nearly absent in bonobos ( Pan paniscus) (but see 11) and orangutans ( Pongo ssp.) 12. Intraspecies violence resulting in lethal injuries occurs in a variety of mammal species 1, and has been suggested to follow patterns explicable by kin selection 2, 3 and evolutionary game theory 4.Ĭoncerning our closest living relatives, the great apes, intraspecific killing has frequently been reported across multiple chimpanzee ( Pan troglodytes) communities e.g., 5– 7 and gorilla ( Gorilla gorilla) 8– 10 groups. In addition, they may aid in combining field data from extant models with the Pliocene hominid fossil record to better understand behavioural adaptations and interspecific killing in the hominin lineage. Our findings may spur further research into the complexity of interspecies interactions. Given these events meet conditions proposed to trigger coalitional killing of neighbours in chimpanzees, we also discuss them in light of chimpanzees’ intraspecific interactions and territorial nature. We discuss these observations in light of the two most widely accepted theoretical explanations for interspecific lethal violence, predation and competition, and combinations of the two-intraguild predation and interspecific killing. In both events, the chimpanzees significantly outnumbered the gorillas and victims were infant gorillas. Here, we provide the first information of two lethal coalitionary attacks of chimpanzees ( Pan troglodytes troglodytes) on another hominid species, western lowland gorillas ( Gorilla gorilla gorilla), that occur sympatrically in the Loango National Park in Gabon. Contrarily, interspecies violence has mainly been investigated in the context of predation and received most research attention in carnivores. Intraspecies violence, including lethal interactions, is a relatively common phenomenon in mammals.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |