Effects of tourists on Barbary macaques at Gibraltar.

Interactions between tourists and Barbary macaques (Macaca sylvanus) at Queen's Gate, Gibraltar, are described. Interaction rates are high, with 99.6 interactions/h at peak times. Macaques spend 13.2% of their day interacting with tourists and 41.9% inactive. An overall ratio of 3.2:1 between human-initiated and macaque-initiated interactions was found. Of interactions involving humans, 85% concerned tourists. Diurnal activity patterns of the macaques were adapted to tourist visitation patterns. Old animals initiated more food-related interactions than younger ones. Infants/juveniles were the commonest class in contacts with humans and vehicles. Interactions involving more than one macaque were rare. High interaction rates were recorded for mothers and babies.