They are most active in the early morning. Feeding bouts are 1-15 minutes long. Spider monkeys have evolved an extremely flexible society to cope with this. They move around the forest either singly or in groups of up to 20. These groups are not permanent, lasting for a few hours, or sometimes for a few days.
Monkeys join or leave, alone or in smaller groups.
This behaviour might give the impression that spider monkey society is fluid and unstructured. However, within any one area the monkeys are divided up into groups. A certain patch of forest might have 2 or 3 groups within it, moving around as smaller subgroups. Whenever 2 subgroups meet, their reaction depends on whether they belong to the same permanent group. If they do, they mingle then divide up later, perhaps along different lines.