The Project

• Within Andean Perú, primates have been known to primarily reside in the eastern Amazonian lowlands; however, many of these same species live in distributions that include both mid and high altitudes [1].

• Larger-bodied primates species such as woolly monkeys (genus Lagothrix) have a much lower population density in western Amazonia in central-eastern Perú [2], but little is known on how this compares to populations in south-east Perú, especially those in montane forests [3].

• Through census surveys, we can work to gain a better understanding of habitat preferences, group compositions, and ranging patterns of primates found at the Soqtapata Concession, as well as identify which groups may be best suited for long-term ecological and behavioral data collection in the future.

• Identify the distribution of primate species/groups along an altitudinal gradient of Andean and Amazonian terrain found at Soqtapata, Perú to a) help clarify taxonomic designation of the primates at this site, and b) better understand their habitat preferences and group compositions.

• In total, we completed 94 census surveys with 19 primate encounters. We identified at least two groups of large-headed capuchins (Sapajus apella macrocephalus) and one group of woolly monkeys (Lagothrix lagotricha sp.). 

• There were an additional 22 encounters with the capuchin monkey groups and 7 encounters with the woolly monkey groups outside of these census periods.

• One group of Sapajus was most often observed along the two trails at higher elevations, while the other group was most often found near the trail at a lower elevation. The average group composition of the Sapajus groups were 2-4 individuals, with two adult males and one adult female with an infant observed simultaneously.

• Lagothrix were only observed along the Ukumari transect, although visitors have observed them near the station at lower elevations. We observed up to 10 woolly monkeys simultaneously, including 2 adult males, 3 adult females, 4 juveniles/subadults, and 1 infant.

Limitations for Unhabituated Groups

While we successfully encountered primate groups during census surveys, there were 29 other primate encounters that occurred outside of census periods, highlighting the limitations of census surveys with unhabituated primates.

The lack of habituation also emphasizes the necessity to shift towards a more multidisciplinary approach in methods. Future research should consider more passive methods of data collection in order to detect the presence or absence of animals at sites that are more difficult to traverse and have limited visibility. Examples may include the use of camera traps or passive acoustic monitors.

Anthropogenic Disturbances

Occasionally during census surveys there were external disturbances aside from researcher presence, such as domesticated dogs or workers engaging in tree removal near the transects. This may have contributed to the lack of primates observed.

[1]  Shanee, S., Shanee, N., Campbell, N., Allgas, N. (2014). “Biogeography and Conservation of Andean Primates in Peru”. High Altitude Primates. Developments in Primatology: Progress and Prospects. pp 63–83. 

[2] Aquino, R., Cornejo, F.M. & Heymann, E.W. (2013). “Primate abundance and habitat preferences on the lower Urubamba and Tambo rivers, central–eastern Peruvian Amazonia”. Primates, 54, 377–383. 

[3] Aquino, R., et al. (2019). “First Inventory of Primates in the Montane Forests of the Pasco and Ucayali Regions, Peruvian Amazon”. Primate Conservation, (33), pp. 1-11.

Field Assistance: (2024 Student Researchers): Maya D’souza, Nicholas Guetersloh, Molly Hearsch, and Kathryn Keeley.

We thank the Peruvian government for permission to work in the Manire region, and everyone involved in the management of operations at SOQTAPATA such as Rafael Pilares and Ana Robles. Funding for this research was provided by the Rebecca Jeanne Andrew Memorial Award, Undergraduate Summer Scholars Program, Dean's Scholar Award, Undergraduate Research Award, and the Center for Career Exploration & Success from Miami University.