Monkeys live together in groups, which help to defend food sources and raise young. These social interactions require some form of communication, and that’s why monkeys have developed many visual and auditory signals. For example, gelada males flip their upper lips back to show off their large canine teeth in a threat or warning. They also jerk their heads and shoulders forward. These and other behavioral cues indicate aggression or readiness to fight.
Most monkeys are arboreal. But a few species, such as baboons and some capuchins, are more terrestrial. They have feet with five digits and a prehensile tail, which is ridged on the underside and flexible enough to hold onto branches or grab other items.
Many monkeys groom each other to express affection and make peace with fellow troop members. They may also use this activity to keep their fur clean of dirt, dander, and parasites. Owners of pet capuchins can encourage these positive behaviors by gently brushing their animals while speaking in a soothing tone.
When it comes to eating, most monkeys are omnivorous. They eat nuts, fruits, leaves, flowers, vegetables, bark, roots, rodents, birds, invertebrates, and even bananas when available.
Many types of monkeys are endangered, or at risk of becoming so. Monkeys in the wild face threats like habitat loss and fragmentation, hunting for bushmeat or traditional medicines, and capture for the international pet trade. Other risks include natural disasters, disease, and competition for limited resources with other species.