True faithfulness? Pair living and monogamy in coppery titi monkeys

Abstract

Pair living is rare amongst mammals in general, but relatively common in primates, and found e. g. in the South American titi monkeys. In a field study on coppery titi monkeys in Peruvian Amazonia we examined the mechanisms of pair living and whether pair living is associated with genetic monogamy. In our study groups, female titi monkeys invested more in pair bonding by grooming the pair mate more often than vice versa and by being more active in the maintenance of spatial proximity between the mates. Males were the exclusive carriers of infants and also were more active in the defense of the territory and against predators than females. We did not find evidence for extra-pair paternities. Taken together, our findings support the “male-services” hypothesis for the evolution and maintenance of pair living in titi monkeys.