Survey of Alouatta caraya, the black-and-gold howler monkey, and Alouatta guariba clamitans, the brown howler monkey, in a contact zone, State of Rio Grande do Sul, Brazil: evidence for hybridization.

Sympatry and natural hybridization between howler monkey taxa (Alouatta spp.) has only recently being confirmed in the wild. Surveys in areas of potential contact between the distribution of two taxa have shown that sympatry is rare, although more common than previously known.