ANBI 133: Great Ape Ecology and Evolution Bonobo Overview February 17, 2021 Bonobo Overview

• Range and taxonomy • Evolution with chimpanzees and gorillas • Ecology • Sex and play Range

• Pan paniscus, “pygmy chimpanzee”, bonobo Evolution

• Bonobo and chimpanzee most recent common ancestor (MRCA) about 1 MYA • Gorillas and bonobo/chimp CA sympatric before 2.5 MYA • Gorillas consume herbaceous leafy diet • Bonobo/chimpanzee CA consume fruit-based diet Evolution

• Significant drought 2.5 MYA in the area that is now the Congo • Gorilla foods disappeared from the area, inferred that gorillas left too • Non-drought conditions return and food is much more abundant in the habitat than comparable chimpanzee habitats • Congo, Lomani, Kasi, and Sankuru rivers limits migration • Chimpanzees north of Congo river Evolution

• Lush habitat along with the available gorilla ‘niche’ makes food more abundant for bonobos • Reduced food competition • Which sex will this affect more? • Larger party size • Increased social tolerance Ecology • Diet: • Frugivorous with significant contribution of terrestrial herbaceous vegetation • High in protein and carbohydrates • Low in fiber and non-digestible materials • Very little meat • Habitat: prefer swampy and rainforest habitats • Activity pattern: diurnal • Locomotion: knuckle-walkers Ecology

• Social organization: multi-male, multi- female, fission-fusion society • Male philopatry (males remain in natal group) • Female centered groups with egalitarian or female/female dominance • Female bonds very strong • What is unusual about this? Bonobos and Sex

• “Make love not war” ape • Sexual behavior and contact frequent, believed to be used to mitigate social tension • Sexual contact between all sexes and age classes • Female/female sex particularly important and frequent • “g-g rubbing” Bonobos and play

• Play occurs in young mammals • What is the function? • Development and growth • Determining rank • Building social bonds • Bonobo play continues into adulthood