Our projects take us to some of the most remote places on the planet in order to learn more about rare, endangered, and ecologically important species, document human impacts on the planet, and work with local partners to protect habitat and wildlife.
Night Monkey Research, Peru
Discover some of our ongoing research with the black-headed night monkey (Aotus nigriceps) in the Manu Biosphere of southeastern Amazon, Peru.
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Publications
“Species distribution and conservation assessment of the black-headed night monkey (Aotus nigriceps): a species of Least Concern that faces widespread anthropogenic threats” evaluates the actual conservation status of A. nigriceps, a nocturnal primate found in the southwestern Amazon. Despite its current IUCN classification as Least Concern, the study reveals that the species faces significant threats from deforestation, agricultural expansion, and habitat fragmentation. Using ecological niche modeling (MaxEnt), the authors found that suitable habitat has declined by approximately 16–19% since 2000, with only 67% of the monkey’s assumed range remaining viable, and just 34% of that within protected areas. Forest loss in the region has eliminated more than 130,000 km² of habitat, potentially displacing or killing over 1.6 million individuals. Projections indicate continued declines if deforestation trends persist. The study urges re-evaluation of the species' status and recommends expanded conservation strategies, including increasing protected areas, supporting REDD+ and agroforestry initiatives, enhancing Indigenous land rights, and improving landscape connectivity to mitigate ongoing threats.
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In southeastern Peru’s Manu Biosphere Reserve, Helenbrook et al. (2020) studied 14 groups of black-headed night monkeys (Aotus nigriceps) to assess their habitat use, fruit consumption, and population density. The monkeys were found exclusively in secondary tropical rainforest dominated by bamboo and cane, with approximately half of the groups selecting bamboo stands as sleeping sites—differing from earlier reports of tree cavity or liana use. Population densities varied between the two study sites, with estimates ranging from 19 to 50 individuals per square kilometer, compared to previously reported averages of 31–34 individuals/km². Dietary analysis, based on seeds recovered from fecal samples, showed a heavy reliance on pioneer plant species such as Cecropiaceae, Piperaceae, and Moraceae. These findings suggest that A. nigriceps is highly adaptable and capable of surviving—and potentially thriving—in regenerating forest and areas near human activity, underscoring its ecological flexibility in altered landscapes.
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Check out our recent night monkey research:
Species distribution modeling and conservation assessment of the black-headed night monkey (Aotus nigriceps) – A species of Least Concern that faces widespread anthropogenic threats
Molecular characterization of Blastocystis in captive and free-ranging New World Primates Platyrrhini, Primates
Intestinal parasitism in free-ranging black-headed night monkeys, Aotus nigriceps, of Southeastern Peru
Habitat use, fruit consumption, and population density of the black-headed night monkey, Aotus nigriceps, in Southeastern Peru
Spatial variation in black-headed night monkey (Aotus nigriceps) vocalizations
Bioacoustics of the black-headed Night Monkey, Aotus nigriceps
Species distribution modeling and conservation assessment of the black-headed night monkey (Aotus nigriceps) – A species of Least Concern that faces widespread anthropogenic threats
Molecular characterization of Blastocystis in captive and free-ranging New World Primates Platyrrhini, Primates
Intestinal parasitism in free-ranging black-headed night monkeys, Aotus nigriceps, of Southeastern Peru
Habitat use, fruit consumption, and population density of the black-headed night monkey, Aotus nigriceps, in Southeastern Peru
Spatial variation in black-headed night monkey (Aotus nigriceps) vocalizations
Bioacoustics of the black-headed Night Monkey, Aotus nigriceps
Night Monkey (or Owl Monkeys)
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TCF conducts research into the bioacoustics, behavior, habitat, and parasitology of night monkeys (Aotus) across the Amazon Basin.
(Photos by Jessica Suarez)
(Photos by Jessica Suarez)
Want more details about our research, visit Primates, Parasites, and Conservation Biology.
Details about upcoming expeditions, visit Expeditions.
Details about upcoming expeditions, visit Expeditions.