Not every day does science add a new mammal to the map of known species. Rarer still is when that mammal is the size of a house cat.
But that is precisely what happened at a wildlife refuge in the Bolivian cloud forest, where a volunteer stumbled across a tilcayo—the first wild cat species described in the region in a century.
A Kitten That Turned Out to Be Something Else
It started simply enough. A man living near a small village in the cloud forest outside La Paz brought an animal to the Senda Verde sanctuary, convinced it was a stray kitten.
Paola Nogales-Ascarrunz, a sanctuary volunteer and director of Bolivia’s Feline Research Program, was skeptical from the moment she saw it. The animal was too small—even for a domestic kitten.
When a second individual with similar characteristics turned up at the same sanctuary not long after, her suspicions hardened into something more serious.
Subsequent genetic analysis of tissue samples from both animals confirmed what Nogales-Ascarrunz had suspected all along.
These were not domestic cats. Nor did they belong to any catalogued species of tiger cat—the common name for small felines of the genus Leopardus, native to Central and South America.
The animals represented a lineage that had diverged genetically from its closest relatives approximately 1.4 million years ago.
That evolutionary distance was enough to lead a team of researchers—including ecologist Tadeu de Oliveira of Maranhao State University in Brazil—to formally describe the new species in the scientific journal Current Biology.
The Tilcayo, the Fifth Tiger Cat of South America
The species was named Leopardus tilcayo, or tilcayo, after the region where it was found.
It is a slender, spotted feline with rounded ears, smaller than the average house cat, adapted to life in the Bolivian Yungas—the cloud forest that forms in the transition zone between the Andes and the Amazon basin.
With this discovery, the number of recognized tiger cat species in South America climbs to five.
What makes the tilcayo especially striking is not just that it’s new to science, but how it was found.
Unlike other recently recognized species—such as the Bornean clouded leopard, identified in 2006 from genetic differences in museum specimens that had existed for decades—the tilcayo had no prior presence in any scientific collection.
It had never been collected, never been studied. The researchers themselves describe this as highly unusual for a mammal of this size. The vast majority of species still being discovered are far smaller creatures: insects, rodents, invertebrates.
Nogales-Ascarrunz was careful to point out, however, that the animal is only new to science. Local communities in the area have known this cat for generations. It simply had never been formally documented by the international academic community.
A Species Born Already Threatened
The discovery comes with sobering news. Researchers believe the tilcayo is endangered from the very moment of its discovery.
Tiger cats as a group face mounting pressure from agricultural expansion and urban development encroaching on their habitats. The Bolivian Yungas are no exception.
For Nogales-Ascarrunz, the discovery adds one more compelling argument for the conservation of a region that, until now, still held secrets that even science had yet to uncover.
The Bolivian Yungas: As Wild as It Is Overlooked
Beyond the discovery itself, the story draws attention to a region that most visitors to Bolivia overlook entirely.
The Yungas form a cloud forest corridor that descends from the Andean peaks near La Paz down into the Amazonian lowlands. The region boasts extraordinary biodiversity packed into a relatively small area.
The town of Coroico, roughly three hours by road from La Paz, serves as the most common gateway to the area—and the reference point for reaching the Senda Verde sanctuary, located just minutes from the nearby village of Yolosa.
The refuge, which rescues animals from illegal trafficking and habitat loss, is open to visitors through guided tours designed to minimize stress on the animals: no physical contact, small groups, access limited to designated observation areas.
It is not a place where you will encounter the tilcayo—a reclusive, newly described animal living wild in the forest. But it offers a responsible way to connect with the wildlife that shares this same landscape, and to understand firsthand why its preservation matters.
The journey to Coroico and the Yungas is itself part of the experience.
Much of the route follows the old Death Road, now reborn as one of the world’s most famous mountain bike descents. The ride drops more than 11,500 feet—from Andean glaciers to subtropical jungle—in just a few hours.
For those who prefer a quieter pace, the same destination is reachable by car or by the minibuses that depart regularly from the La Paz neighborhood of Villa Fatima.
Taken together—the scientific discovery and the landscape that sheltered it—the tilcayo becomes more than a zoological curiosity. It is, if nothing else, a compelling reason to explore one of the most biodiverse and least-visited corners of South America.
