Tourists urged to stop feeding Gibraltar’s famous macaques junk food,
Wildlife experts are urging tourists to stop feeding Gibraltar’s famous macaques, as research reveals the monkeys have started eating soil in response.
Every year, millions of toursits flock to Gibraltar to see barbary macaques, which live on the famous Rock of Gibraltar.
While holidaymakers are advised to keep their distance from the monkeys, many ignore the rules, and lure the animals in with chocolate, crisps, and ice creams.
Now, a study has revealed the desperate steps the monkeys are taking to self–medicate themselves against these junk foods.
Researchers from the University of Cambridge have discovered macaques munching on soil, in a practice known as ‘geophagy’.
The soil helps to soothe the monkey’s stomachs by providing the bacteria and minerals that areabsent from junk food.
‘Foods brought by tourists and eaten by Gibraltar’s macaques are extremely rich in calories, sugar, salt and dairy,’ said Dr Sylvain Lemoine, who led the study.
‘This is completely unlike the foods typically consumed by the species, such as herbs, leaves, seeds and the occasional insect.’
Wildlife experts are urging tourists to stop feeding Gibraltar’s famous macaques, as research reveals the monkeys have started eating soil in response.
Researchers from the University of Cambridge have discovered macaques munching on soil, in a practice known as ‘geophagy’
A population of around 230 monkeys exists on Gibraltar.
They’re the only free–living monkeys in Europe, although they’re not strictly wild, as they’re fed and managed by the Gibraltar Ornithological and Natural History Society and the Gibraltar Veterinary Clinic.
Gibraltar’s tourist website explicitly states that tourists should not feed the monkeys.
‘Please DO NOT feed the monkeys. Processed foods are terrible for their health, not to mention the extreme long term negative effects it has on their social behaviour,’ the website reads.
‘If you are caught feeding the monkeys you may net yourself a fine of up to £4000.’
However, many tourists ignore this advice, and provide junk food to the monkeys.
Dr Lemoine explained: ‘Humans evolved to seek out and store energy–dense fats and sugars to survive periods of scarcity, leading us to crave high–calorie junk food.
‘Availability of human junk food could trigger this same evolutionary mechanism in macaques.’
Gibraltar’s tourist website explicitly states that tourists should not feed the monkeys
In the study, the researchers observed the macaques, and found that animals in frequent contact with tourists ate more dirt, and that dirt–eating rates were higher during peak holiday season
In the study, the researchers observed the macaques, and found that animals in frequent contact with tourists ate more dirt, and that dirt–eating rates were higher during peak holiday season.
Around 30 per cent of soil–eating occurred in groups, while 89 per cent took place in the presence of other macaques who were often watching.
This suggests the behaviour is ‘socially learned’, according to the experts.
In addition, the researchers found that the monkeys clearly favoured certain types of soil.
Most macaques sought out ‘terra rossa’ – a red clay earth – while one troop had acquired a taste for tar–clogged soil from potholes.
‘The emergence of this behaviour in macaques is both a functional and cultural one, like nutcracking in chimps, except it is driven entirely by proximity to humans,’ Dr Lemoine said.
‘We think the macaques started eating soil to buffer their digestive system against the high energy, low fibre nature of these snacks and junk foods, which have been shown to cause gastric upsets in some primates.’
Overall, the findings support the ‘protection hypothesis’, in which macaques eat soil to quell their upset stomachs.
Around 30 per cent of soil–eating occurred in groups, while 89 per cent took place in the presence of other macaques who were often watching
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Dr Lemoine added: ‘The consumed soil acts as a barrier in the digestive tract, limiting absorption of harmful compounds.
‘This could alleviate gastrointestinal symptoms from nausea to diarrhoea.
‘Soil may also provide friendly bacteria that helps with the gut microbiome.’
‘Non–human primates become lactose intolerant after weaning, so dairy is known to cause digestive issues in monkeys, and ice cream is hugely popular with Gibraltar’s tourists and consequently its macaques.’



