Chimpanzee locomotor risk-taking points to the importance of parental and alloparental supervision in humans

Adolescence is generally considered the life stage with peak risk-taking among humans, though this may be specific to the type of risk. To circumvent the safety constraints that limit experiments of physical risk-taking in humans, we used the natural behavior of wild chimpanzees as a model. All chimpanzees must navigate the same arboreal substrates where falls from the tree canopy are a major cause of trauma, and therefore have clear fitness consequences. Using instances of locomotor free flight as a proxy, we found that height from the ground and sex did not predict physical risk-taking. The latter finding is similar to human and chimpanzee economic risk-taking studies. We found that physical risk-taking correlated with age, peaking in infancy and decreasing gradually thereafter through juvenility and adolescence. We hypothesize that a similar pattern would be exhibited in humans if oversight were relaxed earlier in childhood, as it is among chimpanzees.