We assume that allogrooming is an activity which yields various benefits to
the participants and at the same time its practice requires a resource inv
estment. In this work we aim to quantify the costs and benefits derived for
each subject by performing allogrooming in order to find the maximum net b
enefit gained and the equilibrium point above which a major allogrooming in
vestment would not increase the benefits obtained. The data were obtained o
bserving the members of a captive troop (N = 9) of white crowned mangabeys
(Cercocebus torquatus lunulatus) at the Barcelona Zoo. Allogrooming time an
d the preceding and following context were recorded for each actor. The cos
ts were quantified as the energetic expenditure required to perform allogro
oming as proposed by Coelho (1974). The benefits were estimated from the fr
equency and duration of bouts associated to transitions preceded by an agon
istic context and followed by a neutral context. The equilibrium values of
time spent in allogrooming, for which the costs equalled the benefits, and
the value for time invested corresponding to maximal net benefits, were est
imated from the theoretical model adjusted to the data, it was found that t
he differences between the equilibrium point and the maximal net benefit we
re correlated with the age of the subject, which can be understood as an ef
fect of learning the relation cost-benefit of allogrooming to maintain low
levels of agonism within the troop.