Locomotion in bonobos (Pan paniscus): differences and similarities between bipedal and quadrupedal terrestrial walking, and a comparison with other locomotor modes

Abstract

One of the great ongoing debates in palaeo-anthropology is when, and how, hominids acquired habitual bipedal locomotion. The newly adopted bipedal gait and the ancestral quadrupedal gait are most often considered as very distinct, with each habitual locomotor mode showing corresponding anatomical adaptations. Bonobos ( Pan paniscus ), along with common chimpanzees ( P. troglodytes ), are the closest living relatives to humans and their locomotion is valuable for comparison with other primates, and to gain an insight in the acquisition of human bipedalism.Bonobos are habitual quadrupeds, but they also engage in bipedal locomotion, both on terrestrial and in arboreal substrates. In terms of kinematics and dynamics, the contrast between bipedal and quadrupedal walking seems to be more subtle than one might expect. Apart from the trunk being approximately 37 ° more erect during bipedal locomotion, the leg movements are rather similar. Apart from the heel, plantar pressure distributions show subtle differences between bipedal and quadrupedal locomotion. Regardless, variability is high, and various intermediate forms of locomotion (e.g. tripedal walking) exist both in captivity and in the wild. Moreover, there is overlap between the characteristics of walking and other locomotor modes, as we show with new data of walking on an inclined pole and of vertical squat jumps. We suggest that there is great overlap between the many locomotor modes in bonobos, and that the required polyvalence is reflected in their anatomy. This may hamper the development of one highly specialized gait (i.e. bipedalism), which would constrain performance of the other types of locomotion.

Kinematic and EMG Determinants in Quadrupedal Locomotion of a Non-Human Primate (Rhesus)

“…Monkeys do not achieve optimum inverted pendulum-type gait (D'Aout et al 2004) nor do human toddlers (Ivanenko et al 2004a) during their first steps. Development of pendulum mechanisms in infants correlates with the emergence of planar co-variation among lower limb oscillations (Ivanenko et al 2004a).…”

Locomotor versatility in the white-handed gibbon (Hylobates lar): A spatiotemporal analysis of the bipedal, tripedal, and quadrupedal gaits

“…Bonobos, along with chimpanzees, are the closest living relatives of humans (Chen and Li, 2001;D'Août et al, 2004;Goodman et al, 2005), and they occasionally walk bipedally (Susman et al, 1980), which makes them suitable for the study of the evolution of human bipedalism. In addition, it has been suggested that the postcranial morphology of bonobos shows the closest affinity with the morphology of the Pan-hominin ancestor (Zihlman and Cramer, 1978;McHenry and Corruccini, 1981;Payne, 2001).…”

“…Finally, bipedal gait characteristics of gibbons were compared to those of bonobos (Pan paniscus) and humans (Homo sapiens). These species are interesting for comparison, in view of their different morphology, their ability to walk bipedally, and their close phylogenetic relationship with gibbons (McHenry and Corruccini, 1981;Goodman, 1999;Aerts et al, 2000;Vereecke et al, 2003;D'Août et al, 2004;Goodman et al, 2005).…”

Hip joint contact force in the emu (Dromaius novaehollandiae) during normal level walking

“…Primates have only rarely been used for modeling orthopaedic disorders because of ethical concerns and prohibitive expense. They also require substantial training to make their bipedal locomotion resemble that of humans, and they tend to revert to quadrupedal or tripedal (addition of one arm) locomotion in stressful situations (D'Aout et al 2004;Hirasaki et al 2004). Various quadrupeds can be constrained to bipedal locomotion (e.g.…”