Credit: Martin Nicourt/Gibraltar macaques project.Monkeys living on Gibraltar have learned that swallowing soil can quell upset stomachs caused by eating sweet and salty snacks offered by or stolen from holidaymakers, research suggests.Snacks such as chocolate bars, crisps and ice cream have negative digestive effects for the macaques but are "as delicious for them" as they are for humans, according to a Cambridge University study.

Credit: Martin Nicourt/Gibraltar macaques project.Monkeys living on Gibraltar have learned that swallowing soil can quell upset stomachs caused by eating sweet and salty snacks offered by or stolen from holidaymakers, research suggests.Snacks such as chocolate bars, crisps and ice cream have negative digestive effects for the macaques but are "as delicious for them" as they are for humans, according to a Cambridge University study.