|Abstract: The San Martin Titi monkey (Callicebus oenanthe) has one of the smallest geographic ranges of Peruvian primates. Unfortunately for this species, locally known as the mono Tocón, land conversion by humans has decimated its estimated 16,000 km2 extent in northern central Peru. The San Martin Titi monkey is a 'narrow endemic', having a very small geographic range, only occurring within San Martin Department. Currently the species' habitat extent consists of a series of forest fragments surrounded by human agriculture and development and restricted on other sides by higher elevation cloud forests and broad rivers. Little is known about the capacity of the Titi monkeys to traverse among remnant forested patches. In this project, we will amplify ongoing field surveys that focus on habitat remnants to identify which remnants are being used by the species (by calls and visual surveys), and characterize to what extent they are able to use existing corridors.