Evolutionary biology: What's in a baboon's behind?

  title={Evolutionary biology: What's in a baboon's behind?},
  author={Robin I. M. Dunbar},
It is often thought that sexual 'ornaments', such as the swellings that adorn ovulating female baboons, are signalling something about fertility — but what? Long-term studies of wild baboons provide an answer. 

Behavioral Endocrinology and Reproductive Strategies in Wild Female Geladas (Theropithecus gelada).

The female counterstrategies to sexually selected male infanticide and the Bruce effect in wild geladas are studied.

Dominance and reproductive rates in captive female olive baboons, Papio anubis.

It is suggested that social stresses are important suppressors of the hormonal and lactational competence of subordinate females.

Male attacks on infants and infant death during male takeovers in wild white-headed langurs (Trachypithecus leucocephalus).

The data suggest that males kill unrelated and unweaned infants during the takeover period to decrease the time until the infants' mothers resume fertility, which would support sexual selection theory in white-headed langurs.

An Attempt to Explain Visual Aesthetic Appreciation.

We suggest an evolutionary based explanation for why humans are preoccupied with aesthetic aspects of visual input. Briefly, humans evolved to be swayed by positive and negative feelings in the form

Identifying a Facial Expression of Flirtation and Its Effect on Men

Results from experimental studies showed that flirtatious facial expressions, as compared with happy or neutral expressions, led to faster identification of sex words by men, and support the role of flirtatiously expression in communication and mating initiation.

The Passion of Pan



The evolution of conspicuous oestrous advertisement in Old World monkeys

It is argued that prominent oestrous swellings are sexually selected traits that reliably advertise some aspect of a female's quality or condition, and which have evolved because of competition among females to attract males.

The Relationship between Concealed Ovulation and Mating Systems in Anthropoid Primates: A Phylogenetic Analysis

There is a linkage between absence of ovulation signs and monogamy, but the temporal relationship is generally such that the lack of ovulatory signs is more likely to promote monogamy than monogamy is to promote a lack of Ovulatory signs.

The evolution of exaggerated sexual swellings in primates and the graded-signal hypothesis

  • C. Nunn
  • Biology, Psychology
    Animal Behaviour
  • 1999
It is suggested that exaggerated swellings can be viewed as distributions representing the probability of ovulation (the graded-signal hypothesis), which makes testable predictions for future comparative and observational research.

Sexual swellings advertise female quality in wild baboons

It is shown that sexual swellings in wild baboons reliably advertise a female's reproductive value over her lifetime, in accordance with a theoretical model of honest signalling.

Infanticide risk and the evolution of male–female association in primates

A fundamental link between primate life history and social behaviour is demonstrated, the most basic type of variation in primate social organization is explained, and an additional determinant of social organization that may also operate in other mammals is proposed.

Primate Consortships: A Critical Review

A conceptual framework is developed in which variation among male/estrous‐female dyads is characterized in terms of three functionally relevant dimensions: mate assessment, courtship, and mate guarding, which shows inconsistency in the use of the consortship concept is problematic.