Play Behaviour in Free-Living Langur (Semnopithecus entellus) Infants

Piny behaviour in free-living langurs has been studied at Ambagnrh Reserve Forest, near Jaipur, India using focal sampling (Altmann, 1974) for 317 hours on a unimale group of langurs of 102 individuals. Infants were classified as young (dark pelage, birth < 6 months) and old (grey pelage, 6 months to 12-15 months). Observations were recorded in 3 states: infant with mother (state 0), infant less than 2 feet away from mother (state 1) and infant more than 2 feet away from mother (state 2). Unlike old infants, young infants played while on mother and old infants played away from mother and in state 2, play alone, play with other infant and play with juvenile differed significantly (x² = 18.01, df = 2, p < 0.01). Both natural and sexual .selection seem to have played a role. Those patterns have evolved, which are adaptive. Play is replaced by grooming (which strengthens social bonding) in non-human primate and socialization in humans.These traits help in selecting potential mates. Comparison of human and langur infants indicates that young langur infants are comparable to 1st year and toddlers while old langur infants are similar in play profile to preschoolars and elementary . Influences of habitat quality on play behaviour in primates have been discussed.