Monkey business resolved in Gibraltar

Gibraltar’s macaques are considered symbols of British sovereignty Keystone Archive

Gibraltar’s famous Rock Apes, the very symbol of the British outpost at the tip of Spain, are no less than a bunch of immigrants, according to Swiss researchers.

This content was published on April 26, 2005 minutes

Genetic analysis has shown the Barbary macaques are not an indigenous species but descend from Moroccan and Algerian monkeys that were brought to Europe.

For years scientists speculated that the Gibraltar monkeys were an isolated colony, the last representatives of their kind on the continent.

But the Swiss study, published this week in the online edition of the American scientific journal, Proceedings of the National Academy of Sciences, has put paid to this theory.

"We are sure now that Gibraltar’s macaques are not the remnant of an earlier European population," said Zurich University anthropologist Lara Modolo. Results show the British monkeys are clearly related to North African populations.

Macaques - or their ancestors - are believed to have lived in some parts of Europe during the last Ice Age. Some authors have even claimed that they could still be found in Spain in the 1800s.

Working with researchers from Constance University in Germany and Chicago’s Field Museum, Modolo analysed the DNA makeup from 30 per cent of the monkeys and compared it with macaque populations in North Africa.

"We were able to determine the source populations in Morocco and Algeria because they have very distinct genetic markers," she told swissinfo. "These populations were clearly isolated a long time ago from each other."

Local belief

When the macaques were introduced to Gibraltar is still open to debate. According to Modolo, they arrived sometime in the past 2,000 years but it is difficult to be more precise.

The most likely reason is that the Moors brought them to Spain as pets when they occupied the southern Iberian peninsula from 711 onwards.

"If we refer to historical records they most probably arrived before the British took over, somewhere between 1,400 and 700 years ago," added Modolo.

During the Second World War macaque numbers in Gibraltar are believed to have dropped to as low as three because of disease.

The then British prime minister, Winston Churchill, demanded stocks be replenished at all costs. This was done in order to comply with a local belief that if the monkeys died off, Britain would lose its grasp on the strategic Rock.

But today’s colony of macaques is not entirely descended from these animals imported from North Africa between 1942 and 1946.

Modolo admits that a few original monkeys survived the war, but their exact number remains shrouded in mystery. The Rock is peppered with caves where animals have no trouble hiding.

"We only know of reports of macaques being imported from Morocco during and after the war," the anthropologist told swissinfo. "But we have shown that the current population has ties to Algerian monkeys so we know they are the descendants of a much older group."


The number of Barbary macaques living in Gibraltar today totals around 240, in five groups ranging between 37 and 68 animals according to a 2002 census. They are the last wild primates in Europe.

But if the Rock Ape colony gets too big, Gibraltar’s local government allows culling to avoid pressure on a limited habitat. Population control is considered "an essential part of effective management of the [...] colony" says Gibraltar’s natural history society.

Once a common sight in North Africa, only isolated groups of monkeys survive today in Morocco and Algeria. Facing stiff competition from humans for living space, their numbers have dropped by half over the past 20 years to reach just 10,000.

The Barbary macaque is listed as a vulnerable species in the World Conservation Union’s Red List.

swissinfo, Scott Capper

Key facts

Gibraltar’s macaques, often mistakenly called Barbary apes, are one of 20 macaque types, but the only one found outside Asia.
Spanish histories from the 17th century mention monkeys on the Rock of Gibraltar.
When the British took over the Rock in 1704, they found monkeys living in a more or less wild condition.

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In brief

Tradition says that Gibraltar will remain British so long as the monkeys are on the Rock.

They are considered an important symbol of British sovereignty over the outpost.

An early story claims that the macaques saved the enclave from a Spanish invasion during a siege in the late 18th century.

The monkeys were startled by Spanish troops attempting to sneak in and the noise they made alerted the British of the surprise attack.

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