Interindividual variation that is relatively stable over time and consistent across situations is known as personality, among other labels, e.g., temperament (Réale et al. 2007). Darwin suggested that psychological dispositions underlying behavior in animals are subject to natural selection (Darwin 1998/1872). Personality in humans has been studied for a long time—over a century (Galton 1884)—yet a lot of unanswered questions remain. One such question is: how is the variation in personality traits maintained if it is exposed to natural selection? At the beginning of personality studies, variation in the behavior of individuals was believed to be “noise” around an adaptive norm (Huntingford 1976; Réale et al. 2007; Wolf and Weissing 2012). To understand the evolutionary implications of personality requires that one studies personality in different species. Studies of animal personality started quite late compared to the human personality studies for several reasons, including fear of accusations of anthropomorphism (Gosling 2008). Yet, about two decades ago, the number of personality studies of different animal species started to increase. This work took place in multiple taxa, including invertebrates (Kralj-Fišer and Schuett 2014), fish (Millot et al. 2014), birds (Dingemanse et al. 2002), and mammals (Scott and Fuller 1965). Some personality traits in animals were later found to be heritable (Weiss et al. 2000; Dingemanse et al. 2002; Staes et al. 2016). Some studies showed fitness-related outcomes of personality traits, including health, survival, and reproductive success (Capitanio 2011; Dingemanse et al. 2004; Weiss et al. 2013).

Conclusions

For a long time, personality studies were conducted mostly in humans. However, to understand how personality evolved, it helps to conduct studies of personality in other species. Studying the personality of great apes, and especially our closest relatives, bonobos and chimpanzees, can be particularly informative with respect to personality evolution. Because of the association of some personality traits with fitness-related outcomes, such as reproductive success, lifespan, health, and the ability to cope with stress (Norman et al. 2021), great ape personality studies are also important for captive management, animal welfare, or conservation. The first study of wild bonobo personality took place at Wamba field station. This study identified five questionnaire-derived factors and three behavior-derived factors and revealed that personality structure of wild bonobos resembled that of captive bonobos (Garai et al. 2016). The study of the Wamba bonobos also contributed to the field of animal personality with the discovery of polymorphisms with high diversity on four loci of three personality candidate genes (Garai et al. 2014). These loci were associated with aggressiveness, among other traits, in humans. To better understand the evolution of personality, it is important to have more studies focusing on personality structure as opposed to certain single traits, such as boldness. It is not possible to understand the evolutionary background of certain personality traits if we examine them outside of the contexts of all personality traits in any given species. There is also a need to conduct more animal personality studies in the wild. In the case of the great apes, this will be not possible without long-term field stations. Only through sites like Wamba can we gain an insight into the elusive lives of these species.