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 being Mons Abyla or Jebel Musa on the African side of the Strait. In ancient times, the two points marked the limit to the known world, a myth originally fostered by the Greeks and the Phoenicians. Gibraltar is surrounded by the Mediterranean Sea and has no contact with the Atlantic Ocean. The Rock of Gibraltar is a monolithic promontory. The Main Ridge has a sharp crest with peaks over 400 m above sea level, formed by Early Jurassic limestones and dolomites. It is a deeply eroded and highly faulted limb of an overturned fold. The sedimentary strata composing the Rock