There are 5 genera and 24 species, which can be divided into 2 subfamilies: Isostinkbug subfamily and Isostinkbug subfamily. Spider monkeys are distributed in tropical forests in South America. Named for its slender limbs, it looks like a giant spider from a distance when it moves on the tree. The hair is thick and dense, the head is round and small, and the tail is longer than the body length, reaching 80 cm, which is extremely tangled. Small groups feed during the day, and hundreds of large groups can gather at night. When the enemy is hurt, it will give an alarm and keep throwing branches and feces at the invaders. The whistling monkey is large, with a body length of 90 cm, which can exceed 100 cm. The hyoid bone is developed, and it can make a huge roar, which can be heard from 1.5 kilometers away and transmit information.