Abstract: The ability to innovate and the social transmission of innovations have played a central role in human evolution. However, innovation is also crucial for other animals, by allowing them to cope with novel socioecological challenges. Although innovation plays such a central role in animals' lives, we still do not know the conditions required for innovative behaviour to emerge. Here, we focused on interindividual differences in innovation by (1) extensively reviewing existing literature on innovative behaviour in animals and (2) quantitatively testing the different evolutionary hypotheses that have been proposed to explain interindividual variation in innovation propensity during foraging tasks. We ran a series of phylogenetically controlled mixed-effects meta-regression models to determine which hypotheses (if any) are supported by currently available empirical studies. Our analyses show that innovation is more common in individuals that are older and belong to the larger sex, but also in more neophilic and/or explorative individuals. Moreover, these effects change depending on the study setting (i.e. wild versus captive). Our results provide no clear support to the excess of energy or the bad competitor hypotheses and suggest that study setting and interindividual differences in traits related to personality are also important predictors of innovation.

Abstract: Close associations between adult males and lactating females and their dependent infants are not commonly described in non-monogamous mammals. However, such associations [sometimes called friendships (Smuts 1985)] are regularly observed in several primate species in which females mate with multiple males during the fertile period. The absence of mating exclusivity among friends suggests that males should invest little in infant care, raising questions about the adaptive significance of friendship bonds. Using data from genetic paternity analyses, patterns of behavior, and long-term demographic and reproductive records, we evaluated the extent to which friendships in four multi-male, multi-female yellow baboon (Papio cynocephalus) groups in Amboseli, Kenya represent joint parental care of offspring or male mating effort. We found evidence that mothers and infants benefited directly from friendships; friendships provided mother–infant dyads protection from harassment from other adult and immature females. In addition, nearly half of all male friends were the genetic fathers of offspring and had been observed mating with mothers during the days of most likely conception for those offspring. In contrast, nearly all friends who were not fathers were also not observed to consort with the mother during the days of most likely conception, suggesting that friendships between mothers and non-fathers did not result from paternity confusion. Finally, we found no evidence that prior friendship increased a male’s chances of mating with a female in future reproductive cycles. Our results suggest that, for many male–female pairs at Amboseli, friendships represented a form of biparental care of offspring. Males in the remaining friendship dyads may be trading protection of infants in exchange for some resources or services not yet identified. Our study is the first to find evidence that female primates gain social benefits from their early associations with adult males.

Abstract: 1. Dominance/subordinance is a relationship between two individuals in which one defers to the other in contest situations. Each such relationship represents an adaptive compromise for each individual in which the benefits and costs of giving in or not giving in are compared. Familiar associates in groups or neighbours on nearby territories may develop relatively stable dominant-subordinate relationships based on individual recognition. Although the aggressive aspects of dominance are usually emphasized, the less conspicuous actions of the subordinate individual are actually more important in maintaining a stable relationship. 2. In evolutionary terms, dominance essentially equals priority of access to resources in short supply. Usually the subordinate, who would probably lose in combat anyway, is better off to bide its time until better able to compete at another time or another place. Both individuals save time, energy, and the risk of injury by recognizing and abiding by an established dominant-subordinate relationship. 3. Dominance can be either absolute or predictably reversible in different locations or at different times. Of the various forms of dominance behaviour, rank hierarchies and territoriality represent the two extremes of absolute and relative dominance, respectively. A dominance hierarchy is the sum total of the adaptive compromises made between individuals in an aggregation or organized group. Many animals seem to be capable of both absolute and relative dominance, and within species-specific limits the balance may shift toward one or the other. High density, or a decrease in available resources, favours a shift from relative to absolute dominance. Some species may exhibit both simultaneously. Social mammals may have intra-group hierarchies and reciprocal territoriality between groups, while the males of lek species may exhibit 'polarized territoriality' by defending small individual territories, with the most dominant males holding the central territories where most of the mating takes place. 4. Territoriality is a form of space-related dominance. Most biologists agree that its most important function is to provide the territory holder with an assured supply of critical resources. Territoriality is selected for only when the individual's genetic fitness is increased because its increased access to resources outweighs the time, energy, and injury costs of territorial behaviour. 5. Territoriality was first defined narrowly as an area from which conspecifics are excluded by overt defence or advertisement. The definition has been variously expanded to include all more or less exclusive areas without regard to possible defence, and finally to include all areas in which the owner is dominant. I define territory as a fixed portion of an individual's or group's range in which it has priority of access to one or more critical resources over others who have priority elsewhere or at another time. This priority of access must be achieved through social interaction. 6. My definition excludes dominance over individual space and moving resources, and includes areas of exclusive use maintained by mutual avoidance. It differs from most other definitions in its explicit recognition of time as a territorial parameter and its rejection of exclusivity and overt defence as necessary components of territorial behaviour. There is an indivisible continuum of degrees of trespass onto territories, and functionally it is priority of access to resources that is important rather than exclusive occupancy. 7. There is a similarly indivisible continuum in the intensity of behaviour needed to achieve priority of access to resources. Deciding whether or not an exclusive area is defended leads to the pointless exercise of trying to decide which cues indicating the owner's presence are conspicuous enough to merit being called defence. Concentrating on overt defence emphasizes the aggressive aspects of territorial behaviour rather than the equally or more important submissive aspects such as passive avoidance.

Abstract: The evolutionary forces that drive fitness variation in species are of considerable interest. Despite this, the relative importance and interactions of genetic and social factors involved in the evolution of fitness traits in wild mammalian populations are largely unknown. To date, a few studies have demonstrated that fitness might be influenced by either social factors or genes in natural populations, but none have explored how the combined effect of social and genetic parameters might interact to influence fitness. Drawing from a long-term study of wild bottlenose dolphins in the eastern gulf of Shark Bay, Western Australia, we present a unique approach to understanding these interactions. Our study shows that female calving success depends on both genetic inheritance and social bonds. Moreover, we demonstrate that interactions between social and genetic factors also influence female fitness. Therefore, our study represents a major methodological advance, and provides critical insights into the interplay of genetic and social parameters of fitness.

Abstract: Among nonhuman primates, females often form strong bonds with kin and other group members. These relationships are thought to have adaptive value for females, but direct effects of sociality on fitness have never been demonstrated. We present 16 years of behavioral data from a well-studied population of wild baboons, which demonstrate that sociality of adult females is positively associated with infant survival, an important component of variation in female lifetime fitness. The effects of sociality on infant survival are independent of the effects of dominance rank, group membership, and environmental conditions. Our results are consistent with the evidence that social support has beneficial effects on human health and well-being across the life span. For humans and other primates, sociality has adaptive value.