Fury in Gibraltar over what tourists have been feeding its famous monkeys

Gibraltar’s monkey population have started eating mud to settle their stomachs after consuming fast food from tourists, a new study has revealed. Scientists have found that the Barbary macaque population in the British Overseas Territory regularly consume mud and do not believe the behaviour is a one-off or driven by mere curiosity.

Instead, researchers say the mud-eating is likely, as they are provided with fruit, vegetables and seeds each day, but they also get additional food from visitors. The animals are usually fed by local authorities who provide them with fruit, vegetables and seeds each day, but they manage to get their hands on additional food from visitors who are often seen feeding them crisps, chocolate, ice cream, salty peanuts, bread, juice and other snacks. This is despite warnings not to touch or feed the monkeys.

Gibraltar’s Barbary macaques are the only wild monkey population in Europe, numbering around 230, living on the Rock. These tailless monkeys are now a major tourist attraction.

While investigators are not yet certain that the animals’ new behaviour is down to their fast-food consumption, their evidence shows a correlation between interaction with tourists and the amount of mud eaten. This evidence was gathered between summer 2022 and spring 2024 and revealed that almost a fifth of the food consumed by the monkeys was provided by tourists.

Those living nearer to the top of the Rock were twice as likely to eat this type of food and were also those most likely to eat mud. Meanwhile, during the high tourist season, when the availability of human food grows, more monkeys eat mud. During the winter months, the animals were found to be 40% less likely to consume food from tourists and more than 30% less likely to eat soil.

Throughout the investigation, 44 monkeys were observed eating soil on 46 occasions. In three cases, they ate the mud immediately after ingesting ice cream, sweets, or bread.

It is believed that the mud reduces the negative effects of an inadequate diet and therefore benefits the digestive system.

It is not only Gibraltar’s monkeys that are consuming mud in this way – in Africa, Asia and South America, pregnant monkeys have been observed eating soil to reduce nausea and obtain minerals.

With the summer tourist season approaching, visitors have been reminded not to feed the animals or leave litter behind.