But, if the chances of receiving anything in return seem slim, they’ll give up the activity much sooner.
A new study has found that chimps quit grooming others sooner if a higher-ranking chimp is nearby, seemingly to prevent investing too much time on someone who will then turn their attention elsewhere.
The new research led by a scientist at the University of Kent suggests grooming ties in more with an ‘economic-benefits, markets-based approach,’ than a relationship model.
Among the social benefits, it’s also known that grooming helps chimps to reduce stress and remove parasites.
A previous study from Dr Nicholas Newton-Fisher, of Kent’s School of Anthropology and Conservation, found that chimps tend to stop grooming sooner when surrounded when a larger number of chimps are nearby, regardless of rank.
In the new work, the same researcher and colleagues focused on a group with a more defined social hierarchy to see how this influenced their grooming patterns.
The team observed grooming interactions among a community of chimps in the Budongo Forest Reserve in Western Uganda.
And, this revealed that when higher ranking individuals appeared where one chimp was grooming another, the groomer would stop far sooner.
According to the researchers, this suggests the chimps did not want to waste time on a peer who may not reciprocate the activity.
If a higher-ranking chimp than those in the grooming pair has appeared, the researchers explain, the chimp being groomed may instead tend to the new individual next, rather than returning the favour.
‘The extreme degree of structural despotism shown by the males of the Sonso community during this study appeared to have a strong influence on grooming investment strategies,’ the authors wrote in the study, published to the journal Animal Behaviour.
‘Such conditions reflect marked rank differences and the degree to which rank-related commodities such as agonistic support or tolerance are restricted to high-ranked individuals.
‘In contrast to our findings for the substantially more structurally egalitarian M-group, the influence of bystanders on the grooming strategies of Sonso community males was mediated by a strong effect of dominance rank.’