Rock of Gibraltar may have originated from an escape of North African animals transported to Spain; it is also possible that the original Gibraltar macaques are a remnant of populations that are known to have spread throughout Southern Europe during the Pliocene, up to 5.5 million years ago. Some animals of the Rock have been reintroduced by the Alameda Wildlife Conservation Park who have three Barbary macaques. The Rock of Gibraltar, at the head of the Strait, is a prominent headland, which accumulates migrating birds during the passage periods. The vegetation on the Rock, unique in southern Iberia, provides a temporary home for
Rock of Gibraltar Over time, this process can form caves. For this reason the Rock of Gibraltar contains over 100 caves. St. Michael's Cave, located halfway up the western slope of the Rock, is the most prominent and is a popular tourist attraction. Fossils of Neanderthals have been found at several sites in Gibraltar. In 1848, a Neanderthal woman's skull was found at Forbes' Quarry, located on the north face of the Rock. However, its significance was not recognized until after the 1856 discovery of the type specimen in the Neander Valley. Excavations in Gorham's Cave, located near sea level on the eastern