Humans — like most non-human primates — are social beings and profit in many respects from the benefits of a community. However, their closeness to conspecifics is an opportunity for pathogens and parasites to infect new hosts. It is therefore advantageous to avoid sick individuals. Scientists investigated how mandrills recognize conspecifics infected with intestinal parasites and avoid an infection. The monkeys are able to smell an infected group member and consequently groom them less than healthy individuals.