New Sighting Confirms Presence of Grey-bellied Night Monkey in Abra de Zamora 

08/27/2025

In southern Ecuador’s Abra de Zamora, scientists at the Nature and Culture’s San Francisco Scientific Station have just documented a new resident of the montane forests: the grey-bellied night monkey (Aotus lemurinus). This new sighting adds to our understanding of where the species lives and highlights the region as one of the most biodiverse areas of the Andes. 

Located within the páramo linking the Andes with the Amazon, between the provinces of Loja and Zamora Chinchipe, this region is part of a larger network of protected areas. Together with Podocarpus National Park, Nature and Culture’s San Francisco Scientific Station, and nearby municipal reserves, it forms a strategic ecological corridor. Though relatively small in size, the Abra de Zamora mountain pass overflows with life, sheltering an incredible variety of species found nowhere else. It’s especially rich in amphibians and plants, making it one of Ecuador’s most vibrant corners of biodiversity. 

The night monkey had never before been recorded at the San Francisco Scientific Station. This elusive species is notoriously hard to spot, thanks to its nocturnal habits and discreet behavior. It lives in well-preserved cloud and lowland forests like those in Abra de Zamora, feeding on fruits, flowers, sap, insects, and small vertebrates. In doing so, it plays a vital ecological role as a seed disperser and helps drive the natural regeneration of Andean montane forests. 

“The presence of this species in Abra de Zamora had not been previously documented. This is an important data point that helps us understand its current distribution in Ecuador’s Andes,” says Diego Armijos, professor and researcher at the Zoology Museum of the Universidad Técnica Particular de Loja (UTPL), who has led numerous fauna studies in the area. 

A vulnerable species under pressure

While the sighting of the night monkey marks an important scientific milestone, it has also highlighted emerging threats to its survival. The confirmation of its presence coincided with the discovery of a dead individual, electrocuted after coming into contact with high-voltage power lines running through its habitat. This incident underscores the direct impact human infrastructure can have on sensitive species inhabiting high-biodiversity ecosystems. 

Classified as Vulnerable (VU) by the International Union for Conservation of Nature (IUCN), the night monkey faces increasing pressure from hunting, wildlife trafficking, and the loss of its natural habitat due to deforestation, agricultural expansion, and infrastructure development without proper mitigation measures. These combined threats endanger the long-term viability of its populations—even in seemingly well-conserved areas like the Abra de Zamora. 

“This incident should serve as a call to implement strategies to reduce wildlife mortality, such as preventative tree trimming or the use of insulated coverings on power lines,” adds Armijos. 

Science-Based Conservation 

The recording of the night monkey in Abra de Zamora demonstrates the positive impact of protected areas and nature reserves. Podocarpus National Park, the San Francisco Scientific Station, and the Municipal Conservation Areas of Zamora are actively protecting the habitats of key species like the grey-bellied night monkey. Thanks to support from organizations like Rainforest Trust and Nature and Culture International, and the ongoing work of UTPL’s Zoology Museum, essential scientific data continues to be generated. Other recent discoveries include endemic species new to science, such as Pristimantis matildae, Pristimantis samaniegoi, and Pristimantis sagedunnae. 

“Each new record strengthens the case for prioritizing protection of this ecosystem. The Abra de Zamora remains a natural laboratory for science, where fragile species still find refuge,” says Armijos. 

Biologist Felipe Serrano notes that night monkeys of the genus Aotus live in small family groups and have low population densities, occupying territories between 5 and 20 acres. He warns that forest conversion to pasture or infrastructure development poses significant threats to their habitat. Despite nearly three decades of intensive research, scientists continue to discover new species in the region. 

Serrano describes the Abra de Zamora and its surrounding conservation areas as a true ‘species factory,’ where every organism plays a crucial role in keeping ecosystems healthy. He emphasizes the urgent need to conserve, study, and learn from these species through collaboration among local communities, government agencies, conservation groups, and academic institutions.