Lagothrix lugens The Colombian woolly monkey (Lagothrix lagothricha lugens) is a critically endangered subspecies of the common woolly monkey from Colombia.

It was initially thought to be a subspecies of the common woolly monkey (L. lagothricha), but was later reclassified as its own species.

[3][4][5] Among all ateline primates, Colombian woolly monkeys exhibit the most sexual dimorphism in body size.

Males are about forty-five percent heavier than their female counterparts.

[6] However, the cause of this dimorphism remains an enigma as there are no apparent female choice in favor of larger males.