When biologists discover a new species in the 21st century, it's usually because they've run new DNA analysis, peered more closely down the microscope, or collected specimens from far beyond the human comfort zone.

Yale researchers have helped to describe a new species of Colobus monkey living high in the forest canopies of the Democratic Republic of Congo.

Known locally as "Likweli" or "kasaba nkoni," this species may already be threatened.