What influences grooming habits of wild chimpanzees?

Social partners can influence the way an adult male chimpanzee establishes grooming interactions -- an important social interaction for chimps -- with family and community members, new research says.

The chimps' decisions on how much to invest in grooming interactions that are usually done to establish friendly ties are based at least in part on whether there are other potential social partners close by, the findings showed.

With more bystanders - a larger audience - the male chimps offered less grooming at the start of a bout and were more likely to abandon the attempts to start a grooming interaction, explained Nicholas E. Newton-Fisher, anthropologists from the University of Kent in Canterbury, Britain.

Also, their grooming efforts were less likely to be reciprocated, he added.

Chimpanzees grooming involves removing pieces of dirt, plants, dried skin, and insects from the hair of another chimpanzee of off of themselves.

Grooming and other forms of social interaction in non-human primates are driven by considerations of direct benefits rather than relationships based on trust, the study, published in the journal Scientific Reports, revealed.

Wild chimpanzees live in large groups, and the associations between the individual chimps are fluid, and social relationships are variable, the researchers said.

They studied the behaviour of chimpanzees in a 60-strong community from the Mahale Mountains National Park, Tanzania, which has been continuously studied for over 30 years.

The chimpanzees were used to human observation and grooming interactions could be recorded in detail at close range.