Spider Monkeys are diurnal and spend the night sleeping in carefully selected trees. They primarily eat fruits, but will also occasionally consume leaves, flowers, and insects. The diet of Spider Monkeys consists of about 90% fruits and nuts. They eat the fruits of many big forest trees, and because they swallow fruits whole, the seeds are eventually excreted and fertilized by the feces. If food is scarce, they may eat insects, bark and honey.
They are social animals and live in bands of up to 35 individuals but will split up into subgroups of 2 to 8 animals to forage during the day. This social structure (fission-fusion) is found in only two other primate species, the chimpanzee and Homo sapiens.
Also less common in primates, females rather than males disperse at puberty to join new groups. Since the males of this species tend to stick together for their whole life, the males in a group are more likely to be related and have closer bonds than females. The strongest social bonds, however, are formed between females and their young offspring.
The Spider Monkeys may live for 20 years or more. Each female bears only one offspring on average, every 3 to 4 years. The gestation period ranges from 226 to 232 days. Until six to ten months, infants rely completely on their mother, with the males not involved in raising the offspring at all. A mother carries her infant around her belly for the first month after birth, after which she carries the young on her lower back. The infant wraps its tail around its mother’s and tightly grabs her midsection. The mothers are generally attentive and very protective of their young; grabbing their young and putting them on their backs for protection and to help them navigate from tree to tree. Mothers also groom their young.