Capuchin monkey

Capuchin monkeys are highly intelligent New World monkeys belonging to the subfamily Cebinae. They are famous for their cleverness and are often seen in movies or television shows.

These primates live in various tropical environments across Central and South America. Their range extends as far south as northern Argentina. In Central America, some are known as white-faced monkeys, or "carablanca." They often inhabit wet lowland forests on the Caribbean coast or dry forests on the Pacific coast. These monkeys play a vital role in their ecosystems by spreading seeds throughout the forest.

One of the most remarkable features of the capuchin is its brain. They possess the largest brain-to-body ratio of any nonhuman primate. Their brains also feature complex neural wiring. This high level of intelligence likely supports their complex social lives and foraging skills. Because they are so smart, they can mentally map food sources within their territories. This allows them to find food efficiently even when resources are limited.

Scientists categorize capuchins into two main groups based on recent genetic studies. In 2011, researcher Jessica Lynch Alfaro proposed a new classification. She suggested splitting them into the genus Cebus and the genus Sapajus. The gracile capuchins belong to the genus Cebus. They have rounder skulls and longer limbs relative to their body size. The robust capuchins belong to the genus Sapajus. These monkeys have jaws specifically adapted for opening hard nuts. They also feature crests, and the males often grow beards.

Genetic evidence suggests these two groups diverged approximately 6.2 million years ago. Lynch Alfaro believes the formation of the Amazon River caused this split. The river acted as a barrier that separated different populations. The monkeys north of the river evolved into gracile capuchins. Those south of the river in the Atlantic Forest became robust capuchins. This is a clear example of how geography can drive evolution.

Capuchins are omnivores with a very diverse diet. They eat plant parts like fruit, seeds, pith, and even woody tissue. They also consume animals such as arthropods, mollusks, frogs, and crabs. Some capuchins even eat other primates. They are considered extreme foragers because they can find food in many unlikely places. Near water, they use stones to crack open the shells of crabs and shellfish. They have even been observed using stone tools to access large, hard nuts.

Social life is central to the capuchin experience. They live in groups ranging from 6 to 40 members. These groups consist of related females, their offspring, and several males. The social structure usually includes a hierarchy based on age and sex. Often, a single dominant male leads the group. However, in white-headed capuchin groups, both an alpha male and an alpha female lead. They maintain social bonds through mutual grooming and various vocal calls.

Their intelligence is perhaps best seen in their use of tools. Tufted capuchins will carry heavy stones up to a mile to reach a flat boulder. They use these stones to crack open hard fruit to reach the nut inside. This is a complex behavior that young capuchins must learn by watching adults. It can take up to eight years for a juvenile to master this skill. They also use nature to protect themselves from insects. During mosquito season, they crush millipedes and rub them on their backs as a repellent.