The Titi Monkey

General information

The San Martin titi monkey (Plecturocebus oenanthe) was described to science by Thomas in 1924, based on a few collected specimens that are preserved in the Natural History Museum of London. Titi monkeys are small monkeys that can be found in many variations throughout South-America. The adult animals measure (depending on the species) slightly less than 50 centimeters, and have a tail of approximately the same length. They can weight up to one kilograms. The San Martin titi monkey was described as a greyish titi monkey with a whitish band above the eyes. Indeed, many of the animals in the wild are greyish-brown, with a conspicuous white mask. However, the extensive studies carried out by Proyecto Mono Tocón learned us that the coloration of the San Martin titi monkey is very divers, ranging from greyish-brown individuals with a well-marked white ring to much darker or even reddish individuals with no apparent ring. There may even be a correlation between the coloration of individuals and the distribution range of the species, with more animals lacking the white mask in the south than in the north. Additional studies could help us to explain these differences. 

This titi monkey, with the scientific name Plecturocebus Oenanthe, was previously known as Andean titi monkey, but as our studies revealed that its distribution does not reach high altitudes and that the species is endemic to the San Martin Region, it was renamed as the San Martin titi monkey. This name clearly reflects that this species is found exclusively in this department. It is also known locally as mono tocón, llama lluvia (rain caller) or sugkamat (in the native Awajún language).

Before 2007 the species was classified as “vulnerable” on the Red List of Threatened Species (, but that was mainly based on a lack of real information. Once Proyecto Mono Tocón started a detailed study on the status of the species in the wild, it was unfortunately necessary to recategorize its status from vulnerable to critically endangered.

In 2012 the San Martin titi monkey was listed among the “25 most endangered primate species in the world”, stressing the need to take urgent conservation measures. Since then, much work has been done for the conservation of the species, but it is still critically endangered.