Estimating Population Density of the San Martin Titi Monkey (Callicebus oenanthe) in Peru Using Vocalisations.

We calculated the population density of the critically endangered Callicebus oenanthe in the Ojos de Agua Conservation Concession, a dry forest area in the department of San Martin, Peru. Results showed significant differences (p < 0.01) in group densities between forest boundaries (16.