Newborn animals have been observed in the wild in November. Sexual maturity is reached at 4 or 5 years for females and males, respectively. The yellow-tailed woolly monkey is endemic to northern Peru, where it has an extremely limited range. It occurs only in patches of montane Amazon rain forest which intrude as finger-like projections into the Andes. Population figures for this species are unknown.
Preferred habitat is humid and very humid montane rain forest of the Amazonian type.
First described from skins obtained in 1802 by Alexander von Humboldt and then known only from specimens collected in 1925 and 1926, this species was rediscovered by an expedition, which in 1974 obtained four skins, three skulls, and a live specimen that had originally been caught in the upper Tio Mayo area on the eastern edge of its currently known range. Since then, it has been observed in the wild and become the subject of studies. There are no estimates of the initial population, but it is undoubtedly declining. The major threats to the yellow-tailed woolly monkey are habitat destruction and hunting. It seems unable to adapt to secondary forests and is therefore particularly vulnerable to human habitat alterations.