Abstract: The pressures of developing and maintaining intricate social relationships may have led to the evolution of enhanced cognitive abilities in many nonhuman primates. Knowledge of the dominance ranks and social relationships of other individuals, in particular, is important in evaluating one's position in the rank hierarchy and affiliative networks. Triadic interactions offer an excellent opportunity to examine whether decisions are taken by individuals on the basis of such knowledge. Allogrooming supplants among wild female bonnet macaques (macaca radiata) usually involved the subordinate female of a grooming dyad retreating at the approach of a female dominant to both members of the dyad. In a few exceptional cases, however, the dominant member of the dyad retreated; simple non-cognitive hypotheses involving dyadic rank differences and agonistic relationships failed to explain this phenomenon. Instead, retreat by the dominant individual was positively correlated with the social attractiveness of her subordinate companion (as measured by the duration of grooming received by the latter from other females in the troop). This suggests that not only does an individual evaluate relationships among other females, but does so on the basis of the amount of grooming received by them. Similarly, the frequency of approaches received by any female was correlated with her social attractiveness when she was the dominant member of the dyad, but not when she was the subordinate. This indicated that approaching females might be aware of the relative dominance ranks of the two allogrooming individuals. In logistic regression analyses, the probability of any individual retreating was found to be influenced more by her knowledge of her rank difference with both the other interactants, rather than by their absolute ranks. Moreover, information about social attractiveness appeared to be used in terms of correlated dominance ranks. The nature of knowledge acquired by bonnet macaque females may thus be egotistical in that other individuals are evaluated relative to oneself, integrative in that information about all other interactants is used simultaneously, and hierarchical in the ability to preferentially use certain categories of knowledge for the storage of related information from other domains.

Abstract: In recent years evidence has been accumulating that personalities are not only found in humans but also in a wide range of other animal species. Individuals differ consistently in their behavioural tendencies and the behaviour in one context is correlated with the behaviour in multiple other contexts. From an adaptive perspective, the evolution of animal personalities is still a mystery, because a more flexible structure of behaviour should provide a selective advantage. Accordingly, many researchers view personalities as resulting from constraints imposed by the architecture of behaviour (but see ref. 12). In contrast, we show here that animal personalities can be given an adaptive explanation. Our argument is based on the insight that the trade-off between current and future reproduction often results in polymorphic populations in which some individuals put more emphasis on future fitness returns than others. Life-history theory predicts that such differences in fitness expectations should result in systematic differences in risk-taking behaviour. Individuals with high future expectations (who have much to lose) should be more risk-averse than individuals with low expectations. This applies to all kinds of risky situations, so individuals should consistently differ in their behaviour. By means of an evolutionary model we demonstrate that this basic principle results in the evolution of animal personalities. It simultaneously explains the coexistence of behavioural types, the consistency of behaviour through time and the structure of behavioural correlations across contexts. Moreover, it explains the common finding that explorative behaviour and risk-related traits like boldness and aggressiveness are common characteristics of animal personalities.

Abstract: Psychopathology, mental illness, and psychiatric treatment are concepts relevant to modern medicine and medical psychology and replete with cumbersome intellectual and literary baggage. They bear the imprint of suppositions, world views, and general beliefs and values exemplified in the science, history, and general culture of Anglo European societies. The study in higher apes of phenomena addressed by such concepts raises conceptual dilemmas, usually termed speciesism and anthropomorphism, not unlike those encountered in comparative human studies of similar phenomena across cultures and historical periods, namely, ethnocentrism and anachronism. The authors' synthesis of literature and their analysis of the implications of higher ape psychopathology represent an epistemically compelling account that broadens the scope of the comparative study of behavioral irregularities, a topic that provides a different slant for examining challenging questions in evolutionary biology and primatology, such as cognition, self awareness, intentional behavior, culture and behavioral traditions, social intelligence, sickness and healing, and altruism. Theoretical and empirical study of this topic expands formulation and can help provide informative answers about human evolution as well as essential features of human psychiatric syndromes, with potential practical implications. The study of psychopathology of higher apes and other non human primates represents an appropriate focus for neuroscience and bio-behavioral sciences.

Abstract: Recent palaeontological discoveries and the correspondence between molecular and morphological results provide fresh insight on the deep structure of mammalian phylogeny. This new wave of research, however, has yet to resolve some important issues.

Abstract: The place and date of the domestication of the horse has long been a matter for debate among archaeologists. To determine whether horses were domesticated from one or several ancestral horse populations, we sequenced the mitochondrial D-loop for 318 horses from 25 oriental and European breeds, including American mustangs. Adding these sequences to previously published data, the total comes to 652, the largest currently available database. From these sequences, a phylogenetic network was constructed that showed that most of the 93 different mitochondrial (mt)DNA types grouped into 17 distinct phylogenetic clusters. Several of the clusters correspond to breeds and/or geographic areas, notably cluster A2, which is specific to Przewalski's horses, cluster C1, which is distinctive for northern European ponies, and cluster D1, which is well represented in Iberian and northwest African breeds. A consideration of the horse mtDNA mutation rate together with the archaeological timeframe for domestication requires at least 77 successfully breeding mares recruited from the wild. The extensive genetic diversity of these 77 ancestral mares leads us to conclude that several distinct horse populations were involved in the domestication of the horse.