The Amazon region of South America is home to so many different species of animals it can be hard to keep track of who's who, but the black-capped squirrel monkeys tend to stand out from the pack. These tree-dwelling primates have brownish-yellow coats of fur with distinctly darker heads, white masks around their eyes and fuzzy elvish ears. They can be found in many tropical regions from Brazil to Peru and Bolivia, and even as far north as Costa Rica.

The black-headed squirrel monkey is a small creature, typically weighing fewer than three pounds and standing no taller than 11 inches from the head to the base of the tail. There are many different sub-species of squirrel monkeys, and they are typically the same size and share similar coloration and other physical features, with slight variations. For example, the black-capped squirrel monkey's white eye mask has a more rounded arch over the eyes, while other sub-species feature a more dramatic, pointed arch. Their tails are also a bit thinner than those of their relatives.

Males and females within the sub-species are discernible, as the females tend to have darker "caps" of fur on their heads, while the males' coloration is closer to gray than black. Males also gain weight in the months leading up to breeding season, which gives them a bulkier appearance to attract mates. Females will also jump from group to group during mating season to find the perfect partner when it is time to breed, usually during the dry season. They typically give birth once every two years, IUCN Red List reports.

When it comes to feeding, all squirrel monkeys feed mainly upon insects and fruits, but they have also been known to snack on nectar, flowers, seeds, leaves and flower buds. In fact, according to IUCN, the majority of a squirrel monkey's day revolves around foraging for food. They spend most of their time high above the forest floor, swinging through the small branches, but every now and again the monkey may venture down out of the trees to look for food or even a playmate. You should keep your eye on the sky to see these tiny primates, but it wouldn't be too surprising to see one or two scampering across the shores of the Amazon River.