Comparison of hand use and forelimb posture during vertical climbing in mountain gorillas (Gorilla beringei beringei) and chimpanzees (Pan troglodytes).

Objectives: Studies on grasping and limb posture during arboreal locomotion in great apes in their natural environment are scarce and thus, attempts to correlate behavioral and habitat differences with variation in morphology are limited. The aim of this study is to compare hand use and forelimb posture during vertical climbing in wild, habituated mountain gorillas (Gorilla beringei beringei) and semi-free-ranging chimpanzees (Pan troglodytes) to assess differences in the climbing styles that may relate to variation in hand or forelimb morphology and body size.

Materials And Methods: We investigated hand use and forelimb posture during both ascent and descent vertical climbing in 15 wild mountain gorillas and eight semi-free-ranging chimpanzees, using video records obtained ad libitum.

Nut-cracking behaviour in wild-born, rehabilitated bonobos (Pan paniscus): a comprehensive study of hand-preference, hand grips and efficiency.

There has been an enduring interest in primate tool-use and manipulative abilities, most often with the goal of providing insight into the evolution of human manual dexterity, right-hand preference, and what behaviours make humans unique. Chimpanzees (Pan troglodytes) are arguably the most well-studied tool-users amongst non-human primates, and are particularly well-known for their complex nut-cracking behaviour, which has been documented in several West African populations. However, their sister-taxon, the bonobos (Pan paniscus), rarely engage in even simple tool-use and are not known to nut-crack in the wild.

Within arm's reach: Measuring forearm length to assess growth patterns in captive bonobos and chimpanzees.

Objectives: Bonobos and chimpanzees are known to differ in various morphological traits, a dichotomy that is sometimes used as an analogy for evolutionary splits during human evolution. The aim of our study was to measure the forearm length of immature and adult bonobos and adult chimpanzees to assess the extent of age-related changes of forearm length in bonobos and sex-dimorphism in bonobos and chimpanzees.

Materials And Methods: As a proxy of somatic growth we measured forearm length of captive bonobos and chimpanzees ranging in age from 1 to 55 years.

Fibre type composition in the lumbar perivertebral muscles of primates: implications for the evolution of orthogrady in hominoids.

The axial musculoskeletal system is important for the static and dynamic control of the body during both locomotor and non-locomotor behaviour. As a consequence, major evolutionary changes in the positional habits of a species are reflected by morpho-functional adaptations of the axial system. Because of the remarkable phenotypic plasticity of muscle tissue, a close relationship exists between muscle morphology and function.