The yellow-tailed woolly monkey (Oreonax flavicauda) is a rare primate species found only in the Peruvian Andes, in the departments of Amazonas and San Martin, as well as bordering areas of La Libertad, Huánuco, and Loreto. It is counted as one of the world's 25 most endangered primates and is one of the rarest and largest Neotropical primates, and one of Peru's largest endemic mammals. This species lives in the montane cloud forests of the Peruvian Andes at elevations of 1,500–2,700 m above sea level, a unique cloud forest ecosystem characterized by steep gorges and ravines which forms one of the water sources of the Amazon basin.

The yellow tailed woolly monkey is one of the least studied primates, making informed conservation action difficult. The main threat to the species is the continued expansion of human populations at some of the highest rates in Peru, partly solicited by the proliferation of new mining concessions, which are associated with road construction, habitat destruction and hunting. Climate change is also an increasing threat to the species.

Conservation is made more difficult by farmers’ fear of losing their farmland (which they use for coffee growing and cattle pastures) to conservation efforts. Conserving the yellow-tailed woolly monkey while maintaining the livelihood of the farmers is a key issue in this programme.

This is addressed by community-based conservation efforts by NPC (Neotropical Primate Conservation) and others. Awareness-building education about the critically endangered monkey population and its habitat has helped local people in some of the more remote villages in Amazonas and San Martin understand the importance of preserving this asset which may serve as a tourist attraction.

Moreover, a tree nursery operating in the village of La Esperanza was set up by NPC in 2007, and its management has now been taken over by a group from the village. The nursery produces tress from nine native species. NPC has also established capacity building events for local guides and attempts to prevent further immigration into the species’ native area and to facilitate ecosystem protection initiatives.