Of 709 consecutive instances of grooming recorded in 2001, when there were
10 adult males and 17 adult females, the highest number of approaches for grooming
was made by Maani, the second highest ranking male, with 8.9%. Jambo, also a high
ranking male, scored 5.8% and Duane, the alpha male, scored 3.7%. The highest
number of approaches for grooming by a female was made by Nambi, the alpha female,
with 2.0%. Males thus initiated grooming more often than females.
The highest score for receiving grooming was achieved by Duane, the alpha male,
with 10.9% of all cases. Black, third ranking male, scored 6.9% and Maani, second
ranking male, scored 6.5%. The highest scoring female was Nambi, alpha female, with
2.0%. Males thus not only initiated (see above) but also received more grooming
than females.
Of these 709 cases of grooming, 306 were mutual, i.e. during the grooming session
the chimpanzees involved groomed each other. The highest frequency for mutual
grooming was achieved by Maani (second ranking male) with 32.0% of all mutual
cases. Duane (alpha male) was involved in 25.3% of cases. Black (third ranking male)
in 23.3% of cases. Tinka (omega male) was involved in 4.8% of cases. Nambi (alpha
female) was involved in 4.7% of cases, of which 68% were with Duane. Most other
cases of mutual grooming involved males, sometimes in groups of 3, 4, or even 5.
Mutual grooming is thus a very male activity.
Adult males are highly selective about whom they groom. Newton-Fisher (1997), in
the course of his study of the Sonso males, made a special analysis of 81 occasions of
grooming by adult males. In those instances when 3 or more males were present,
Grooming and other affiliative behaviours 111Fig. 6.1: Nora grooming her mother Nambi (photo: N. Newton-Fisher).