The stress of human encroachment on ape habitats is leading to ape communities self-medicating themselves with leaves in attempts to make themselves healthy.
Scientists have long been aware than chimpanzees use plant leaves to purge intestinal worms from their body – but researchers in Bulindi, Uganda, have noted that now the chimps, stressed by humans, are swallowing more and more leaves, with little benefit to their health.
The researchers, from Oxford Brookes University, tracked the apes across their area, monitoring their route and sampling their faces.
They inspected the droppings for whole leaves, as well as intestinal parasites like nematodes and tapeworms, and noticed the disturbing trend.
Lead author Dr Matthew McLennan, a specialist at Oxford Brookes University, said: ‘At other sites it’s rare to find the undigested leaves in more than one or two in 100 dung samples.
‘At Bulindi it was more like one in ten. So it’s happening at a different order of frequency than in less disturbed landscapes.
Some suggestions as to the illness of the apes are that they are picking up new infections from people and farm animals, and Discovery News highlights one case where a chimp was found to be carrying a kind of tapeworm normally seen in chickens.
This highlights a two-way risk: if apes and humans live in cramped quarters, parasites might end up being spread across both species.
The paper also showed concern about the two species living so close, pointing out that the chimps cannot find enough food in smaller areas, causing them to raid farms in times of need.
McLennan said: ‘It’s a bad situation for everyone – people’s activities are changing the landscape and affecting the chimps’ behaviour – if they can’t get enough to eat in the forests, they start looking for food in people’s fields.
‘Chimpanzees are big wild animals and can be very dangerous; it’s not surprising that local people are afraid of them, so they harass them and try to drive them off. But it turns into a vicious cycle, because it can make the chimps more aggressive.’
Source: Mail Online