In primates, trait covariance is common among limb segments and bony structures. Trait covariance signifies the changes in one trait that may influence the development and/or evolution of another trait. Evolvability - or the ability for a trait to respond to evolutionary pressures - is affected by trait covariance. Covarying traits may limit a trait’s ability to respond to selective pressures, and that traits with high covariance have high integration and low evolvability.

In this study, we estimate measures of evolvability (evolvability, responsibility, integration, and autonomy) of limb segments of common chimpanzees (Pan troglodytes). We hypothesize that the covariance between the humerus, femur, and tibia will follow established patterns for great apes and that the humerus will be less integrated than the femur or tibia. After controlling for sex, results support our hypothesis: that the covariance pattern is as expected and that the humerus is less integrated (and therefore less evolvable) than the bones of the lower limb.