It seems that spider monkeys can be quarrelsome feeders if they are too close to one another, and this spacing out saves them all trouble. During those months of the year when they have to depend on small, scattered sources of fruit, such as from palm trees, lone individuals and smaller aggregations are found moving through the forest. Thus, they avoid quarrelling at food sources with only enough ripe fruit at any one time to feed a few monkeys. Within the group, adult males can coexist peacefully, although there is a clear hierarchy determined by age. The group is centred on the females and their young.
Males are dominant over females, but it is the females that make the key decisions for the group.
Males may forage in small groups. Females and offspring often forage alone. While some females may choose to mate with several different males in a single day, other female-directed pairings can last up to three days. Black spider monkeys mate face to face, as do gibbons, bonobos, orang-utans, capuchins and a few other primate species. The baby clings to mum's tummy for the first four months and later rides piggy-back, wrapping its tail around mum's tail for additional security.