Owl monkeys are widely distributed across southern Central America and northern South America (Groves 2001). A. lemurinus subspecies are found in Panama, northern Colombia, and northwestern Venezuela while A. hershkovitzi ranges only in Colombia. The other gray-necked species include A. trivirgatus, which occupies a range extending from eastern Colombia and southern Venezuela into part of northern Brazil and A. vociferans, which is widely distributed across Colombia, northern Brazil, northern Peru, and eastern Ecuador (Groves 2001). All of the gray-necked species live north of the Amazon River while the red-necked owl monkeys are found south of the Amazon. A. miconax is limited to a very small region in northwestern Peru; A. nancymaae occupies a small region straddling the Peru-Brazil border and is sympatric with both red-necked (A. nigriceps) and gray-necked species (A. vociferans); A. nigriceps is found in Brazil and Peru, and A. azarae subspecies are found in Paraguay, Argentina, southern Bolivia, and Brazil (Groves 2001; Fernandez-Duque et al. 2001).
Little research has been conducted on Aotus in the wild probably primarily due to the difficulty of studying nocturnal primates (Sussman 2000). Research on owl monkeys requires not only specialized forest skills, including the ability to maneuver through the forest at night and good auditory and nocturnal visual skills, but radio-tracking equipment as well (Sussman 2000; Aquino & Encarnación 1994). Some of the intrepid owl monkey researchers and contributors to the knowledge of wild Aotus include Patricia Wright (Peru and Paraguay), Rolando Aquino and Filomeno Encarnación (Peru), and Eduardo Fernandez-Duque (Argentina). Captive studies of Aotus have been conducted at the New England Primate Research Center.