Tsaobis Baboon Project - Recent Projects

Evolution of Social Behaviour

We have adopted a modelling approach to investigate the evolution of social behaviour. Our focus to date has been the emergence of behavioural synchrony and leadership in group foragers. Using dynamic game-theoretic models, we have found that the foraging behaviour of two individuals can quickly become sychronised, and that the hungriest of the pair is most likely to spontaneously emerge as the pacemaker or "leader" (Rands et al. 2003). Our models suggest that individuals in foraging pairs should follow a simple rule-of-thumb: "if I’m hungry, I should forage; if not, then I should copy what my colleague is doing". We have subsequently used an individual-based modelling approach to explore the emergent properties of this rule-of-thumb in larger social groups (Rands et al. 2004).

This work was funded by the Natural Environment Research Council.

Publications:

Rands SA, Pettifor RA, Rowcliffe JM & Cowlishaw G (2004) State-dependent foraging rules for social animals in selfish herds. Proceedings: Biological Sciences 271: 2613-2620.

Rands SA, Cowlishaw G, Pettifor RA, Rowcliffe JM & Johnstone RA (2003) The spontaneous emergence of leaders and followers in foraging groups. Nature 423: 432-434.
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Vigilance Mechanisms and Processes

Vigilance is a fundamental component of anti-predator behaviour in many animals. Hence, among female baboons at Tsaobis, it is no surprise that vigilance primarily serves to reduce the risk of predation. However, vigilance can also have other purposes. Thus, among male baboons (who are less vulnerable to predators), the main use of vigilance appears to be the monitoring of potential female mates and male competitors (Cowlishaw 1998). Analysis of comparative patterns of baboon vigilance between the Tsaobis population and the de Hoop population (in South Africa) indicates that females in both populations appear to be following similar rules of thumb in their vigilance behaviour (Hill & Cowlishaw 2004). More recently, we have developed a model of the costs of vigilance, which is likely to have generality across a wide range of taxa, and tested this model in a primate social forager system very similar to the Tsaobis baboon system (Cowlishaw et al. 2004).

This work was funded by the Natural Environment Research Council and the Association for the Study of Animal Behaviour, with additional support from the Central Research Fund (University of London), the Boise Fund, and the Namibia Nature Foundation.

Publications:

Cowlishaw G, Lawes MJ, Lightbody M, Martin A, Pettifor R & Rowcliffe JM (2004) A simple rule for the costs of vigilance: empirical evidence from a social forager. Proceedings: Biological Sciences 271: 27-33.

Hill RA & Cowlishaw G (2002) Foraging female baboons exhibit similar patterns of antipredator vigilance across two populations. In: Eat or be eaten: predation sensitive foraging in primates (ed LE Miller), pp.187-204. Cambridge University Press: Cambridge.

Cowlishaw G (1998) The role of vigilance in the survival and reproductive strategies of desert baboons. Behaviour 135: 431-452.
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Ecology and Competition

Baboons make complex behavioural trade offs between their needs to find food, avoid predators, and successfully reproduce. Research at Tsaobis indicates that ecological factors, such as the plant community in which the baboons forage (see Cowlishaw & Davies 1997), can be less important than social factors, particularly the risk of infanticide. Our observations suggest that the need to defend infants from attack is a more important determinant of spacing than either predation risk or feeding competition: hence males tend to stay in close proximity to females with infants whom they are likely to have sired (Cowlishaw 1999). Similarly, during group encounters, males appear to evaluate mating opportunities in neighbouring groups (to which they might later transfer), rather than defend ecological resources. In contrast, females appear to use group encounters to either solicit males (if near to ovulation), or avoid them if they have a vulnerable infant (Cowlishaw 1995).

This work was funded by the Natural Environment Research Council, with additional support from the Central Research Fund (University of London), the Boise Fund, and the Namibia Nature Foundation.

Publications:

Cowlishaw G (1999) Ecological and social determinants of spacing behaviour in desert baboon groups. Behavioural Ecology and Sociobiology 45: 67-77.

Cowlishaw G & Davies JG (1997) Flora of the Pro-Namib Desert Swakop River Catchment: community classification and implications for desert vegetation sampling. Journal of Arid Environments 36: 271-290.

Cowlishaw G (1995) Behavioural patterns during baboon group encounters: the role of resource competition and male reproductive strategies. Behaviour 132: 75-86.
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Predation Risk and Anti-Predator Strategies

Research on the Tsaobis baboon population began with a study of predation risk and anti-predator behaviour. Baboons are at serious risk of predation by leopards (Cowlishaw 1994), and the Tsaobis baboons adopt a variety of strategies to reduce this risk. When foraging, for example, the baboons actively avoid the richest habitats if predation risk is high there, preferring safer lower-quality habitats in which to feed. Similarly, the baboons choose the safest habitats to conduct non-foraging activities such as grooming (Cowlishaw 1997a). In addition, over the course of the day, the Tsaobis baboons routinely use refuges, such as trees and cliffs, to reduce predation risk (Cowlishaw 1997b). Individuals in most groups appear to stay on refuges wherever possible, and to stay close to refuges if they cannot be on them. Because females and members of smaller groups perceive the greatest risk of predation (Cowlishaw 1997c), the use of refuges is most prevalent among these animals.

This work was funded by the Natural Environment Research Council, with additional support from the Central Research Fund (University of London), the Boise Fund, and the Namibia Nature Foundation.

Publications:

Cowlishaw G (1997a) Trade-offs between foraging and predation risk determine habitat use in a desert baboon population. Animal Behaviour 53: 667-686.

Cowlishaw G (1997b) Refuge use and predation risk in a desert baboon population. Animal Behaviour 54: 241-253.

Cowlishaw G (1997c) Alarm calling and implications for risk perception in a desert baboon population. Ethology 103: 384-394.

Cowlishaw G (1994) Vulnerability to predation in baboon populations. Behaviour 131: 293-304.
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Evolution of Female Sexual Signals

A crucial constraint on reproductive success in female baboons is the loss of infants to infanticidal male attacks. In response to this threat, females have adopted a variety of counterstrategies. Our analysis indicates that the loud calls performed by females during copulation may be one such counterstrategy. The calls appear to incite male-male competition, which helps to ensure that the female copulates with as many males as possible. This confuses offspring paternity, and thus reduces the likelihood that these males will attempt infanticide subsequently (O’Connell & Cowlishaw 1994, Cowlishaw & O’Connell 1996).

This work was funded by the Natural Environment Research Council and the Association for the Study of Animal Behaviour, with additional support from the Central Research Fund (University of London), the Boise Fund, and the Namibia Nature Foundation.

Publications:

Cowlishaw G & O'Connell SM (1996) Male-male competition, paternity certainty and copulation calls in female baboons. Animal Behaviour 51: 235-238.

O'Connell SM & Cowlishaw G (1995) The post-copulation withdrawal response in female baboons: a functional analysis. Primates 36: 441-446.

O'Connell SM & Cowlishaw G (1994) Infanticide avoidance, sperm competition and mate choice: the function of copulation calls in female baboons. Animal Behaviour 48: 687-694.