When Portuguese explorers reached the Americas in the 15th century, they found small monkeys whose coloring resembled these friars, especially when in their robes with hoods down, and named them capuchins.

[1] When the scientists described a specimen (thought to be a golden-bellied capuchin) they noted that: "his muzzle of a tanned color, ... with the lighter color around his eyes that melts into the white at the front, his cheeks ..., give him the looks that involuntarily reminds us of the appearance that historically in our country represents ignorance, laziness, and sensuality.

"[2] The scientific name of the genus, Cebus comes from the Greek word kêbos,[3] meaning a long-tailed monkey.

The species-level taxonomy of this subfamily remains highly controversial, and alternative treatments than the one listed below have been suggested.

[10] According to genetic studies led by Lynch Alfaro in 2011, the gracile and robust capuchins diverged approximately 6.2 million years ago.

[13] The oldest known crown platyrrhine and member of Cebidae, Panamacebus transitus, is estimated to have lived 21 million years ago.

[14] Capuchins are black, brown, buff or whitish, but their exact color and pattern depends on the species involved.

On average, they weigh from 1.4 to 4 kg (3 to 9 pounds) and live up to 25 years old in their natural habitats,[citation needed] and up to 35 in captivity.

This is because they spread their seed leftovers and fecal matter across the forest floor which helps new plants to grow, therefore adding to the already abundant foliage that shelters the capuchin.

[17] Capuchin monkeys often live in large groups of 10 to 35 individuals within the forest, although they can easily adapt to places colonized by humans.

The stabilization of group dynamics is served through mutual grooming, and communication occurs between the monkeys through various calls.

Young capuchins will watch this process to learn from the older, more experienced adults but it takes them 8 years to master this.

[29] After several months of training, the monkeys began exhibiting behaviors considered to reflect an understanding of the concept of a medium of exchange that were previously believed to be restricted to humans (such as responding rationally to price shocks).

[30] When presented with a reflection, capuchin monkeys react in a way that indicates an intermediate state between seeing the mirror as another individual and recognizing the image as self.

Males made more eye contact than with strangers or familiar monkeys but reacted with signs of confusion or distress, such as squealing, curling up on the floor, or trying to escape from the test room.

[32] This has, however, been repudiated as conclusive evidence for a theory of mind as the monkeys may have learned to discriminate knower and guess by other means.

[35] Since capuchins have a high reproductive rate and can adapt to different living environments, they can survive forest loss more than some other species; however, habitat fragmentation is still a threat.

[36] Predators include jaguars, cougars, jaguarundis, coyotes, tayras, snakes, crocodiles, birds of prey, and humans.

[1] Easily recognized as the "organ grinder" or "greyhound jockey" monkeys, capuchins are sometimes kept as exotic pets.

Ross Geller (David Schwimmer) on the NBC sitcom Friends had a capuchin monkey named Marcel.