New World monkeys only live in South and Central America. Because there have never been any other primate groups there, the New World monkeys have occupied all the ecological niches for primates. They range from tiny marmosets to quite large spider monkeys. Depending on the species and season, they eat insects, fruit, seeds or even resin. Most New World monkeys are diurnal.

In spider monkeys, the tail is so flexible and sensitive that it is used as a fifth hand when climbing.

In the group of marmosets (Liszt’s monkeys, Kaiserschnurr’s bearded monkeys, etc.), only the dominant female reproduces (a bit like ants). The father of the children and many other helpers take part in rearing the young.

There are various group structures in non-marmosets. In some species they are strictly hierarchical and in others promiscuous (everyone with everyone).