Abstract: Alloparenting in Tibetan macaques was studied with point and focal animal sampling methods in the second half of the 1987 birth season (between March and June). The groups were provisioned by tourists in warm seasons and might be observed closely. Within the first 23 weeks, infants were caretaken by alloparents for 10.5% of their time (7.3% with adult males, 1.9% with non-mother adult females, and 1.3% with juveniles), mainly adult males. In comparison with the females, males involved more often in caretaking, inspecting, retrieving and rejecting infants. They played only with male infants. Females showed more curiosity to newborns and inspected them earlier. Juveniles played with infants most often, but involved in other interactions least often. The intensive alloparenting may be selected to compensate the mother's high investment to offspring under poor foraging condition. The "sexual discrimination" to infants may be traced to mothers' greater care for daughters than for sons and the "cute" responses to the erecting penis of male infants.

Key words: Macaca thibetana; Alloparenting; Sexual discrimination