The Rock's most famous inhabitants are its 160 tailless Barbary macaques. Many hang around the Apes' Den near the middle cable-car station, as well as at the top cable-car station and the Great Siege Tunnels. Legend has it that when the macaques (possibly introduced from North Africa in the 18th century) disappear from Gibraltar, so will the British. Summer is ideal for seeing newborns, but keep your distance to avoid run-ins with protective parents, and never feed or touch the macaques.
When numbers were at a low ebb during WWII, the British brought in simian reinforcements from Africa. Recently, however, the macaques' numbers have been increasing rapidly and a range of control measures, from contraceptive implants to sterilisation and 'translocation' to European zoos, have been implemented.