A macaque on the Rock of Gibraltar clutches a tube of crisps.
Monkeys in a tourism hotspot have learned that swallowing dirt can quell the upset stomachs caused by overconsumption of sweet and salty snacks fed to them by holidaymakers, a University of Cambridge study suggests.
Troops of macaques living on Gibraltar – the only free-ranging monkey population in Europe – have been scientifically observed for the first time regularly engaging in “geophagy”: the practice of intentionally ingesting soil.
Researchers monitoring monkey groups across the Rock of Gibraltar have tracked instances of geophagy, and found that animals in frequent contact with tourists eat far more dirt, and that dirt-eating rates are higher during peak holiday season.
The scientists believe that the chocolate, crisps and ice cream offered by or stolen from tourists – a substantial part of some Gibraltar macaques’ diets – are disrupting “gut microbiome composition” in the animals and leading to changes in their culture.
