The brown-spider monkey, Ateles hybridus, is known for its long, slender limbs, prehensile tail, and tree-dwelling lifestyle. But few people know it well. This extremely rare, critically endangered species has virtually disappeared from the forests of Colombia, its native home.

Now, a new finding offers a glimmer of hope for the brown-spider monkey’s survival. Researchers from WCS’s Colombia Program and Colombia’s National Parks Unit have spotted it living in Selva de Florencía National Park. That makes Selva the only national protected area with a confirmed population of this extremely rare primate.

The brown-spider monkey is considered one of the world’s 25 most threatened primates. It resides in two separate populations on either side of the Magdalena River in central Colombia, partially within the Eje Cafetero landscape. Each population represents a different subspecies: A. hybridus hybridus living on one side of the river, A. h. brunneus on the other. While the former subspecies was known to occur in national protected areas, the latter was not, until this recent discovery.

“This exciting discovery of brown spider monkeys in Selva de Florencía National Park emphasizes the importance of protected areas to safeguard wildlife—even for previously unknown species,” said Julie Kunen, WCS Director of Latin America and Caribbean Programs. “The fact that the species was found in a protected area gives conservationists hope that populations will be safeguarded and can perhaps even grow in number.”

When Selva de Florenica became a national park in 2005, the only known known evidence of A. h. brunneus was a captive specimen living with colonists in the park. Subsequent studies were unable to record the species in the area and researchers feared it had gone locally extinct.

Then, in early November of last year, a farmer in the village of El Silencio reported a possible sighting, setting into motion a rapid exploration of the area by officers of the National Parks Unit and researchers from WCS. The search yielded observations of at least two brown-spider monkeys.

Unfortunately, Selva de Florencia National Park is located in the southernmost area of the species’ range; thus the population is even more vulnerable to extirpation. To ensure the continued survival of the brown spider monkey in Colombia, conservationists will evaluate its status in Selva and restore degraded habitat to provide connectivity with northern populations currently being studied by WCS.

For more information, read the press release.