White-cheeked Spider Monkey

• Common Name: White-cheeked Spider Monkey
• Taxonomy Classification Year: 1809
• Monkey Size: 34 to 51 cm (13 to 20 in)
• Skin Color(s): Dark brown or black
• Habitat: Rainforest
• Diet: Herbivorous
• Native Countries: Brazil

The white-cheeked spider monkey^[1] (Ateles marginatus), also known as the white-whiskered spider monkey, is a New World Monkey native to the Amazon Basin of central Brazil.

• Its range is limited by the Xingu River, the Teles Pires River, the Tapajós River, and the Amazon River.
• They live in the highly biodiverse lush lowland rainforests for which the region is known. White-cheeked spider monkeys are primarily black or dark brown, with white fur on their chins, foreheads, and, as their name suggests, cheeks.
• Like all spider monkeys, they have incredibly long legs, arms, and a prehensile tail that helps them swing gently from branches.
• Spider monkey tails have more vertebrae than non-prehensile tails of other primates, and the vertebrae are smaller.
• As a result, the tail is more flexible and extends more than other primates’ tails.
• To help them keep their balance, the underside of their tail is furless and textured like a fingerprint; in fact, their tails are so helpful that they are often called the “fifth limb” or “third hand” of monkeys.
• Unlike most other primates, they do not have an external thumb but instead use their hands as hooks.
• This is actually a peculiar adaptation to their arboreal lifestyle: their ancestors had opposable thumbs, but spider monkeys evolved so that their thumb bones tapered, so they were not visible from the outside.
• Like other spider monkeys, white-cheeked spider monkeys do not exhibit much sexual dimorphism.

• White-cheeked spider monkeys are diurnal and exclusively arboreal. Consequently, they spend most of their lives in the upper levels of the canopy.
• These spider monkeys are known to be suspensive, meaning they spend most of their time hanging from branches.
• White-cheeked spider monkeys live in large groups with an average size of 25 individuals.
• They fend off predators by barking and shaking near branches. If the predator is not frightened by this, it breaks off and throws small branches at it.
• They are considered polygamous, with males mating with multiple females but females mating with only one male.