The Douroucoulis, also called Night Monkeys and Owl Monkeys, as the name indicates, are active at night.
They are small monkeys native to jungles/forests of Central and South America.
The several species of Night Monkey are divided into two groups, the red-necked, further down the page, with ginger chest fur,
and the grey-necked above and immediately below. Spix's Night Monkey,
Aotus vociferans, (shown) is in the grey-necked group.
Spix's is native to southern Colombia, eastern Ecuador, part of far northern Peru and northwestern Brazil.
Above is the Bolivian subspecies of Azara's Night Monkey, Aotus azarai/azarae boliviensis.
Like other Night Monkeys, it lives in mainly monogamous pairs with the father taking on most parental care of offspring.
Apologies for poor pictures but I don't like to use flash on animals.
Above is the Black-headed Night Monkey, Aotus nigriceps, native to Bolivia,
Peru, Colombia and Brazil.
Tame and active in daylight in a park in Peru.