As of January 2015, there are about 2,000 Yucatan spider monkeys left in the wild on the Yucatan Peninsula. There are only an estimated 300 to 400 woolly spider monkeys left in the world.
These are two of the nine species of spider monkey listed by the International Union for the Conservation of Nature (IUCN).
The variegated or brown spider monkey (Ateles hybridus) was on the IUCN’s list of The World’s 25 Most Endangered Primates, 2008-2010. As of 2015, the IUCN lists three species of spider monkey as critically endangered, five species as endangered and one species as vulnerable.
Spider monkey species are endangered primarily due to habitat loss from farming and logging, because they depend on large areas of forest for survival. They are also hunted as a food source for humans.