Part I - Behavioural flexibililty 1. Multivariate and phylogenetic approaches to understanding chimpanzee and bonobo behavioral diversity 2. Chimpanzees in the dry habitats of Assirik, Senegal and Semliki Wildlife Reserve, Uganda 3. Behavioural adaptations to water scarcity in Tongo chimpanzees 4. Bonobos of the Lukuru Wildlife Research Project 5. Grooming-hand-clasp in Mahale M Group chimpanzees: implications for culture in social behaviours Part II - Social relations 6. Factors influencing fission–fusion grouping in chimpanzees in the Taï National Park, Côte d’Ivoire 7. Ecological and social correlates of chimpanzee party size and composition 8. Agonistic relations among Kanyawara chimpanzees 9. Relationships of male chimpanzees in the Budongo Forest, Uganda 10. Dynamics in social organization of bonobos (Pan paniscus) Part III - Female strategies 11. Why female bonobos have a lower copulation rate during estrus than chimpanzees 12. Social relationships between cycling females and adult males in Mahale chimpanzees 13. Seasonal aspects of reproduction and sexual behavior in two chimpanzee populations: a comparison of Gombe (Tanzania) and Budongo (Uganda) 14. Costs and benefits of grouping for femalechimpanzees at Gombe 15. The cost of sexual attraction: is there a trade-off in female Pan between sex appeal and received coercion? Part IV - Hunting and food sharing 16. Variations in chimpanzee–red colobus interactions 17. How bonobos handle hunts and harvests: why share food? 18. Hunting and meat sharing by chimpanzees at Ngogo, Kibale National Park, Uganda Part V - Genetic diversity 19. The evolutionary genetics and molecular ecology of chimpanzees and bonobos