The semi-wild macaques of Gibraltar

Spain is in the midst of picking a fight with Britain over Gibraltar’s sovereignty, so it’s an excellent opportunity to highlight the fact that “the Rock” is one of the more unique nature preserves in all of Europe.   Scientists believe that the peninsula’s mild climate and abundant caves helped shelter otherwise-vulnerable plants and animals (including pre-modern humans) during the last Ice Age.  As a result, the 2.64 square mile area flourished into a hot spot for biodiversity.  It boasts over 600 plant species, a rich array of wildlife, and a prominent avian observatory that monitors migratory patterns of raptors and other Mediterranean seabirds.

Most famously, Gibraltar is home to Europe’s only contingent of free-roaming Barbary macaques (Macaca sylvanus).  Genetic studies estimate that macaques originated in Africa 5.5. million years ago and quickly expanded northward to what is now the Iberian peninsula.  It is possible they once covered the entire Eurasian continent too, but for whatever reason, they soon became rare outside of North Africa.  It is likely that Barbary macaques were introduced to Gibraltar permanently during the naval wars of the late 17th century (the British took control of the colony in 1704).  Because they lack tails, they’re colloquially called  “apes” even though their closest genetic cousins are Asiatic gibbons and baboons.  Their soft pink faces, pale-grey fur, and rust colored heads make them look very congenial and approachable to humans; in fact, macaques were recently studied for insight into the origin of smiling.

Outside of Gibraltar, however, Barbary macaques have been living on the brink for the past several decades.  Relentless development, logging, and other human activities in Morocco and Algeria have driven them out of the high cedar forests and disrupted mating patterns.  With precipitous population decline in former strongholds like Morocco’s Middle Atlas mountain range, the species landed on the International Union for Conservation of Nature’s Red List.  One estimate indicates that there may be fewer than 10,000 remaining worldwide.  The Gibraltar Ornithological and Natural History Society lists 230 currently living in Gibraltar in a “semi-wild” state.  They are allowed to range freely, but the colonies are closely monitored and cared for when needed.  Residents are fiercely protective of their simian “natives,” making The Rock one of the last reliable bastions for this unique and threatened species.

An apocryphal legend holds that if the Barbary “apes” ever leave Gibraltar, the British will soon follow.  As World War II wound down, Winston Churchill (keeping one eye on then-Fascist Spain) took the superstition seriously enough to import macaques in order to reinforce the colony’s population.  And history shows that the British don’t like to give up their territorial holdings without a fight (see: The Falklands, Prince William’s recent deployment to).  Does that bode well for the macaques, too?


Modolo, L. Salzburger, W. Martin, R.D. 2005.  Phylogeography of Barbary macaques (Macaca sylvanus) and the origin of the Gibraltar colony. Proceedings of the National Academy of Sciences of the United States of America. 102(20):7392-7.

Carrión, J. et al. A coastal reservoir of biodiversity for Upper Pleistocene human populations: palaeoecological investigations in Gorham’s Cave (Gibraltar) in the context of the Iberian Peninsula. Quaternary Science Reviews, 2008; 27 (23-24): 2118 DOI:10.1016/j.quascirev.2008.08.016

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