Barbary macaques in Gibraltar

As of 2020[update], some 300 animals in five troops occupy the Upper Rock area of the Gibraltar Nature Reserve, though they make occasional forays into the town.

[1] In his work Historia de la Muy Noble y Más Leal Ciudad de Gibraltar (History of the Very Noble and Most Loyal City of Gibraltar), written between 1605 and 1610, Alonso Hernández del Portillo, the first chronicler of Gibraltar, wrote: "But now let us speak of other and living producers which in spite of the asperity of the rock still maintain themselves in the mountain, there are monkeys, who may be called the true owners, with possession from time immemorial, always tenacious of the dominion, living for the most part on the eastern side in high and inaccessible chasms.

"In his History of Gibraltar (1782), Ignacio López de Ayala, a Spanish historian like Portillo, wrote of the monkeys: "Neither the incursions of Moor, the Spaniards nor the English, nor cannon nor bomb of either have been able to dislodge them.

"[2][3][4]Repeated introduction of animals and the lack of reliable data concerning founders of the Gibraltar macaque population has obscured their origin.

[5] Indeed, it had been earlier suggested that the original Gibraltar macaques were a remnant of populations that had spread throughout Southern Europe[6] during the Pliocene, up to 5.5 million years ago.

During warm interglacials it reached as far north as Germany and Britain, while retreating to southern glacial refugia during cold periods.

[citation needed] The species' disappearance from Europe in the latest Pleistocene, as opposed to its survival during earlier glacial periods, is not fully understood, but is assumed to be due to climatic deterioration and associated vegetation change, perhaps in combination with human pressure.

Any ill or injured monkey needing surgery or any other form of medical attention was taken to Royal Naval Hospital Gibraltar and received the same treatment as would an enlisted service man.

A photograph captured the Queen feeding a Barbary ape while the Duke of Edinburgh stood next to battle-dressed ape-keeper Gunner Wilfred Portlock.

Since Barbary macaque females reproduce well, the population on Gibraltar is steadily increasing, which in turn puts pressure on the limited habitat.

[26] In 1942 (during World War II), after the population dwindled to just seven monkeys, UK Prime Minister Winston Churchill ordered their numbers be replenished immediately from forest fragments in both Morocco and Algeria because of this traditional belief.