The loudest monkey is the Howler Monkey; the most acrobatic is the Spider Monkey. Monkeys can live up to 45 years in captivity. Monkeys' main predators are eagles, hawks, and humans.

Habitat: Monkeys live in forests, grasslands, high plains, and mountain habitats. Many monkeys are arboreal (spending most of their lives in trees); others (like baboons and macaques) live mostly on the ground.

Diet: Monkeys eat leaves, fruit, seeds, nuts, grass, roots, eggs, insects, spiders, and small mammals.

Anatomy: Adult monkeys range from about 2 to 4 feet (0.6 to 1.2 m) long. Most also have a long tail - up to 3 feet (0.9 m) long. They weigh from 4 ounces=113 g (the pygmy marmoset) to 100 pounds=45 kg (the mandrill). Monkeys have long arms; their five-fingered hands and feet have opposable thumbs.

Classification:Kingdom Animalia (animals), Class Mammalia (mammals), Order Primates, Family Cercopithecidae (Old World monkeys) and Family Cebidae (New World monkeys).

Monkeys are divided into two groups, Old World monkeys (from Africa, Asia, and Europe) and New World monkeys (from the Americas).