Grooming between male chimpanzees at Ngogo, Kibale National Park. II. Influence of male rank and possible competition for partners

Dp. Watts, Grooming between male chimpanzees at Ngogo, Kibale National Park. II. Influence of male rank and possible competition for partners, INT J PRIM, 21(2), 2000, pp. 211-238
Citations number
Categorie Soggetti
Animal Sciences
Journal title
ISSN journal
0164-0291 → ACNP
Year of publication
211 - 238
SICI code
Allogrooming contributes to the development and maintenance of social relat ionships, including those that involve alliances, in many primate species. Variation in relatedness, dominance rank, and other factors call produce va riation in the value of others as grooming partners. Several models have be en developed to account for variation in the distribution of grooming in re lation to dominance ranks. These start front the premise that individuals a re attracted to high-ranking partners, but time limits, direct competition, and prior grooming engagement between high-ranking individuals can constra in access to them. Sambrook et al. (1995) formalized same of these models a nd showed the importance of taking group size variation into account when a ssessing them. Chimpanzees form multimale communities in which males are th e philopatric sex. Males commonly associate and groom with each other; they also form dominance hierarchies and form alliances that influence dominanc e ranks and mating success. Both male rank and the rank distance between pa rtners are significantly correlated with the distribution of grooming betwe en males in an extremely large chimpanzee community at Ngogo, Kibale Nation al Park, Uganda, that has more males than any other known community. High-r anking males had more grooming partners than mid- or low-ranking males. Gro oming predominantly went up the dominance hierarchy but was also concentrat ed among males that were close in rank. Rank and rank distance apparently b oth affected grooming independently of reciprocity in grooming and independ ently of the frequency with which males associated in temporary parties. Ho wever, the data no not clearly indicate how constraints on access to partne rs might have operated. Published data from a smaller chimpanzee community at Mahale show no rank or rank distance effect on male grooming. These resu lts and earlier, conflicting findings on the association between dominance rank and grooming in male chimpanzees indicate that variation in group size , i.e., the number of males per community, probably influences the strength of any such effects, as happens for grooming between females in several ce rcopithecine species. Data on coalitions at Ngogo support the argument that high-ranking males are valuable social partners, and similarity in strateg ies of alliance formation may influence the distribution of grooming.