When frightened, woolly monkeys tend to swing through tree branches and hide.

They are closely related to both the spider monkeys and the woolly monkeys.

The hair of the yellow-tailed woolly monkey is long and thick, an adaptation to its cold montane forest habitat.

The population of gray woolly monkeys in Bolivia have been reported to be found as low as 700 meters above sea level.

The tail length of the gray woolly monkey is on average from 66 to 68 cm in length.

The male gray woolly monkey weighs an average of 9.5 kg.

The female gray woolly monkey weighs an average of 7.7 kg.

One story from the western Amazon reported several hunters who killed over 200 woolly monkeys in less than two years, which lead to their local extinction.

The gray woolly monkey is currently protected in many national parks.

The following is a list of protected areas in Brazil where the gray woolly monkey occurs or may occur.