The Development of Primate Raiding: Implications for Management and Conservation

Ecosystems and habitats are fast becoming human dominated, which means that more species, including primates, are compelled to exploit new human resources to survive and compete. Primate “pests” pose major management and conservation challenges. I here present the results from a unique opportunity to document how well-known individuals and groups respond to the new opportunity to feed on human foods. Data are from a long-term study of a single population in Kenya at Kekopey, near Gilgil, Kenya. Some of the naïve research baboons became raiders while others did not. I compare diet, activity budgets, and home range use of raiders and nonraiders both simultaneously, after the incursion of agriculture, and historically compared to the period before agriculture appeared. I present measures of the relative benefits (female reproduction) and costs (injuries, mortality, and survivorship) of incorporating human food into the diet and discuss why the baboons raid and their variations in raiding tendencies. Guarding and chasing are evaluated as control techniques. I also suggest conflict mitigation strategies by identifying the most likely options in different contexts. I end with a proposal for a rapid field assessment of human wildlife conflict involving primates

Maternal Condition Does Not Influence Birth Sex Ratios in Anubis Baboons (Papio anubis)

Trivers and Willard predicted that when parental condition has differential effects on the fitness of male and female offspring, parents who are in good condition will bias investment toward the sex that benefits most from additional investment. Efforts to test predictions derived from Trivers and Willard's model have had mixed results, perhaps because most studies have relied on proxy measures of parental condition, such as dominance rank. Here, we examine the effects of female baboons condition on birth sex ratios and post-natal investment, based on visual assessments of maternal body condition. We find that local environmental conditions have significant effects on female condition, but maternal condition at conception has no consistent relationship with birth sex ratios. Mothers who are in poorer condition at the time of conception resume cycling significantly later than females who are in better condition, but the sex of their infants has no effect on the time to resumption of cycling. Thus, our findings provide strong evidence that maternal condition influences females' ability to reproduce, but females do not facultatively adjust the sex ratio of their offspring in relation to their dominance rank or current condition

The long lives of primates and the ‘invariant rate of ageing’ hypothesis

This work was supported by NIA P01AG031719 to J.W.V. and S.C.A., with additional support provided by the Max Planck Institute of Demographic Research and the Duke University Population Research Institute.Is it possible to slow the rate of ageing, or do biological constraints limit its plasticity? We test the ‘invariant rate of ageing’ hypothesis, which posits that the rate of ageing is relatively fixed within species, with a collection of 39 human and nonhuman primate datasets across seven genera. We first recapitulate, in nonhuman primates, the highly regular relationship between life expectancy and lifespan equality seen in humans. We next demonstrate that variation in the rate of ageing within genera is orders of magnitude smaller than variation in pre-adult and age-independent mortality. Finally, we demonstrate that changes in the rate of ageing, but not other mortality parameters, produce striking, species-atypical changes in mortality patterns. Our results support the invariant rate of ageing hypothesis, implying biological constraints on how much the human rate of ageing can be slowed.Publisher PDFPeer reviewe

Prospects for management of primate pests

Among the variety of commensal relationships between human and nonhuman primates, those of most concern today center around « conflict ». As part of a long-term study of olive baboons (Papio anubis) in Kenya, we had the opportunity to investigate the response of four wild troops to the incursion of agriculture. We also tested a variety of management techniques. The development of crop-raiding was not inevitable. In fact, baboons appeared very reluctant to raid, except for a few who had previously fed on human food. Responses ranged from enlarging home range size, decreasing troop size, shifting home range, to raiding as a secondary strategy and raiding as the main foraging orientation. Crops provided greater digestibility and increased foraging efficiency over natural foods. Eating human food altered activity budgets, increased growth and reproduction, but took its toll in injuries and deaths. Control techniques work through increasing costs and decreasing benefits of raiding. The most promising technique is taste aversion conditioning, although better emetics are needed before this method can be widely used. Shifting cultivars may also be effective, particularly if the new crops are less digestible or less palatable for baboons. The prospects for managing primate pests will vary depending on whether animals have viable alternatives. The future of existing primate commensalism is threatened by increasing human pressure on resources. It is highly unlikely that new commensal relationships will develop given these same constraints. Nevertheless, the framework of primate commensalism may provide insights into the variety of human and nonhuman primate relationships and how these might be manipulated for future primate conservation.Parmi les nombreux types de relations commensales entre l’homme et les primates non-humains, les plus problématiques sont aujourd’hui les situations de conflit. Au cours d’une étude de longue durée des babouins olive (Papio anubis) au Kenya, nous avons pu étudier la réponse de 4 troupes de babouins sauvages à l’irruption de l’agriculture. Nous avons expérimenté plusieurs techniques pour réduire les conflits ainsi créés. Le développement du comportement de pillage n’était pas inévitable, les babouins se montrant très prudents, à l’exception des individus ayant déjà consommé des aliments d’origine humaine. Nous avons observé diverses formes de réponse à cette perturbation d’origine agricole : accroissement du domaine vital, réduction de la taille des groupes, changement de zone, et enfin pillage comme ressource annexe ou principale. Les cultures sont plus digestes que la nourriture naturelle et de récolte facile. L’apport de nourriture humaine a ainsi modifié les budgets d’activité, accéléré la croissance individuelle et le taux de reproduction, mais aussi prélevé son tribut en blessures et mortalité. Les techniques de contrôle sont basées sur l’accroissement des coûts et la diminution des bénéfices liés au pillage des plantations. Parmi ces techniques, la plus prometteuse est l’aversion alimentaire conditionnée, bien que les émétiques actuels ne se prêtent pas à un usage généralisé de la méthode. Une autre solution serait le remplacement des cultures actuelles par de nouvelles cultures, moins digestes ou moins appréciées des babouins. Le résultat des mesures prises dépendra en tout état de cause de l’existence de solutions de remplacement alimentaires viables pour les babouins. L’avenir de relations commensales stables entre l’homme et les babouins est toutefois compromis par la pression croissante de l’homme sur les ressources naturelles. Il est très peu probable que de nouvelles associations commensales se forment au vu de ces dernières contraintes. Néanmoins, l’étude du commensalisme des primates permet d’éclairer la diversité des relations entre l’homme et les primates non-humains, ces connaissances permettront dans l’avenir d’assurer au mieux la conservation des primates.Strum Shirley C. Prospects for management of primate pests. In: Revue d'Écologie (La Terre et La Vie), tome 49, n°3, 1994. pp. 295-306

Sources of variation in condition at conception.

<p>Sources of variation in condition at conception.</p

Maternal condition at conception influences time to resumption of cycling after the birth of (a) nonsurviving and (b) surviving infants.

<p>Maternal condition at conception influences time to resumption of cycling after the birth of (a) nonsurviving and (b) surviving infants.</p