A New Species of Marsupial Has Been Discovered in a Remote Peruvian Forest
In 2018, a research expedition in Peru’s Río Abiseo National Park stumbled upon an animal no scientist had recorded before. Instead of the mysterious squirrel they had hoped to find, the team uncovered a small marsupial later named Marmosa chachapoya. It was identified as a new species after years of study and confirmation.
Researchers carefully analyzed its DNA, skull, and body structure to ensure it had never been described before. The discovery was finally announced in 2025, which added a rare entry to the record of South America’s mammals and underscored the importance of conserving this remote forest.
The Appearance of Marmosa Chachapoya
The marsupial has a delicate body only four inches long, though its tail nearly doubles its overall length. Its reddish-brown fur provides camouflage in the dense vegetation of the Peruvian cloud forest. Dark patches around its eyes form a mask-like pattern that stands out against its lighter face. Consequently, large, round black eyes give it an alert appearance, particularly noticeable in photographs taken during the expedition.
The animal’s elongated snout and distinctive skull features were crucial in setting it apart from other known species of mouse opossums. Experts documented these physical details carefully by comparing them with specimens in collections across several continents. These comparisons confirmed the animal was genetically and morphologically different enough to justify naming it as an entirely new species.
Every detail, down to its dental structure, helped establish the evidence that Marmosa chachapoya had not yet been found, despite resembling some of its relatives.
Discovery in an Unusual Habitat
The discovery took place at 8,740 feet above sea level, right on the eastern slope of the Andes. Scientists had not expected to find a mouse opossum at this altitude, since closely related species are usually recorded much lower. The unusual location provided the first clue that this marsupial might be something previously unknown.
The research team, led by Cal Poly Humboldt biologist Silvia Pavan, had originally traveled to Río Abiseo National Park to investigate a different mammal: an unrecorded species of squirrel. Instead, they encountered a creature that changed the focus of their expedition.
Only one specimen of Marmosa chachapoya was collected, which highlighted how uncommon this species may appear. The park itself is known for being difficult to reach, which makes sightings of little-studied animals more likely during scientific fieldwork than casual visits. Its rough, isolated terrain has long hidden species that escape documentation, which adds weight to the importance of sustained exploration.
Honoring the Chachapoya People
Image via Pexels/Alejandro Novoa
The team chose to name the marsupial after the Chachapoya, an Indigenous culture that lived in northern Peru long before the Inca conquest in the fifteenth century. Often referred to as the “people of the cloud forest,” they built homes and structures on mountain ridges across the Andes. Many archaeological sites related to their civilization lie within the boundaries of Río Abiseo National Park, and they link this animal’s finding with the area’s human history.
By naming the marsupial Marmosa chachapoya, professionals created a direct acknowledgement of that cultural heritage. The Chachapoya inhabited this rugged area from around A.D. 800 until they were absorbed by the expanding Inca Empire.
Their choice of terrain, usually damp and mountainous, mirrors the habitat where this marsupial was finally spotted. Connecting the animal’s identity to the Chachapoya people preserves a tie between modern science and the ancient communities that once called these forests home.