Barbary macaques have a diet of fruit, young leaves, bark, roots and occasionally invertebrates. During the winter when food is scarce they forage for bark and evergreen needles (4). As social animals they live in troops of 12 to 60 (average approximately 24) individuals with females forming the core of the troop. Where there is abundant food and little human interference the home range sizes are smaller (2). Males will establish a hierarchy based on the outcome of competitive interactions, though ranking orders change regularly as males age, leave or enter the troop. The strongest and most successful males become dominant and generally do most of the mating, although all males in the troop may potentially mate with females (5). Reproduction may be somewhat seasonal, with births corresponding to highly productive seasons. Females give birth to a single offspring every one or two years, after a gestation of about five months, and twins are rare. The young are weaned after 12 months, and reach sexual maturity at 2.5 and 4 years old in females and 4.5 and 7 years old in males (5).
The mating system of this species is fascinating. Females mate with all male members of the troop, so males can never be sure of paternity (4). This promiscuous behaviour encourages males to look after one, or some of the young troop members, spending time grooming, protecting and playing with them, despite not knowing if they are their offspring (5). This may seem like an unselfish act, protecting another macaque’s offspring, but because all males in the troop do the same, it is the only way the males can ensure that their offspring will survive. Young females remain within their natal group once they attain sexual maturity, whereas males disperse from their natal group. Becoming accepted into another group is, therefore, critical in the reproductive success of any individual male (5).