The Black howler (Alouatta caraya), is a species of howler monkey native to northeastern Argentina, eastern Bolivia, eastern and southern Brazil, and Paraguay. Together with the Brown howler (Alouatta guariba), it is the southernmost member of the Alouatta genus. Only the adult male is black; adult females and juveniles of both genders are overall whitish to yellowish-buff. However, variations occur even among the adult males; some have patches of reddish-brown or buff fur.