An Unlikely but Crucial Return: Guanacos Come Back to El Impenetrable After 110 Years
January 16, 2026
Photo by Horacio Barbieri / Rewilding Argentina
After local extinction more than a century ago, five guanacos were released in December at El Impenetrable National Park in northern Argentina. The first of multiple planned releases, this large herbivore’s return to the Dry Chaco contributes to ecosystem recovery, mitigating intensifying fire risks and adding to wildlife-watching opportunities within this emerging tourism destination.
“In the absence of guanacos, the ecosystems of El Impenetrable have been severely degraded,” according to Sebastian Di Martino, director of conservation for Rewilding Argentina. “The guanaco’s essential ecological function is to shape landscapes through grazing, allowing for greater plant diversity to eliminate the dry vegetation that causes fires and to redistribute essential nutrients. The pressures brought on by the climate crisis makes the role of guanacos even more crucial.”
Photo by Miranda Volpe / Rewilding Argentina
“Nawananga, what we call the guanaco, were all over the Chaco in ancient times, but they disappeared with the arrival of settlers,” recalls Montiel Romero, a member of the Indigenous Qom community. The species is South America’s largest wild camelid — known as Lu’hüt by the Wichi, and Guasukaka by the Guaraní — and inhabited open grasslands with patches of scrubland and savanna-like environments.
The guanaco left its mark on place names and the chronicles of travelers who explored these regions before the species disappeared. Among the place names near El Impenetrable, Pampa de los Guanacos is perhaps the best known.
Hunting and the loss of grasslands through livestock farming and intentional fires rendered the guanaco practically extinct in the Dry Chaco, a region roughly the size of Bolivia. Only about 100 individuals survive on the border between Paraguay and Bolivia, while near El Impenetrable the species had completely disappeared.
The released individuals come from a healthy population residing in Patagonia National Park, where Rewilding Argentina identified a viable source population for reintroductions. The guanaco transfer involved years of preparation, planning, new herding, capture, and transport techniques, and coordination between Rewilding Argentina, the National Parks Administration, and local provincial governments.
Photo by Miranda Volpe / Rewilding Argentina
The herding effort to capture guanacos within Patagonia National Park depended on successful precision and teamwork. A thorough understanding of the terrain and possible escape routes were key to ensure safe and efficient management. The capture technique consisted of a controlled herding operation with four motorcycles arranged in a “V” formation, guiding the animals toward a funnel that led to a loading chute. It was crucial to respect the guanacos’ social groups, ensuring they were not separated or transported in groups with young offspring, prioritizing animal welfare at all times.
The herding was a success, and the guanacos moved on to the next stage: transport. One aspect for a successful translocation was the design and construction of an appropriate trailer. For this, Rewilding Argentina consulted and worked with South African experts in wildlife transport.
Photo by Horacio Barbieri / Rewilding Argentina
The trailer was designed so that the guanacos could travel comfortably and without risk of injury, whether from the transport process itself or from aggression among themselves. It features various structures for handling guanacos without causing unacceptable levels of stress — subdividing groups according to social cohesion, continuous monitoring of behavior, regulation of the ambient temperature, and even the administration of deworming and vaccinations without entering the trailer. Assessments during transport have indicated that throughout the journey, the guanacos have exhibited calm behavior, with no deaths occurring on any of the numerous trips already made.
The 2,000-mile translocation from Patagonia to El Impenetrable is the longest-ever overland movement of wild animals for conservation purposes. Weather conditions are especially important for this trip. The transport takes place during the colder months, and attention must be paid to the presence of strong winds in Patagonia or rain in El Impenetrable. To fine-tune different aspects of the journey, practice translocations were carried out, initially local movements and then translocations to intermediate points.
Photo by Miranda Volpe / Rewilding Argentina
Once at El Impenetrable, the guanacos were placed in pre-release enclosures to acclimatize. For guanacos, this stage has lasted more than a year, during which they feed on up to 30 species of native plants, including cacti and local fruits. In their first full Chaco winter, the guanacos developed a much less dense coat than the characteristic wool that covers them in Patagonia. The best sign that the animals had adapted to their new environment was the birth of several offspring, both last year and this year, with survival rates similar to those in their native habitat.
Photo courtesy Rewilding Argentina
The gates of the pre-release corrals at El Impenetrable were opened for the first family group in December. These animals were part of those translocated during 2024, and more releases of other groups will take place soon. All the released guanacos wear collars that emit a VHF radio signal and also collect GPS coordinates, which are transmitted via satellite. This allows for assessment of their adaptation to life in the wild and their movements within the environments of the Chaco region’s El Impenetrable.
Efforts are underway to recover other native species at El Impenetrable, including the red-footed tortoise, giant otter, and jaguar.
A driving force to curb the worldwide climate emergency and the biodiversity crisis, Tompkins Conservation protects, rewilds, and defends land and marine ecosystems in the Southern Cone through collaborating to create national parks and rewilding key species. Working with public and private partners, the organization has helped to create 13 national parks, protecting 14.5 million acres. The goal is to restore a healthy planet with big, wild, and connected landscapes where animals and plants can thrive. This also means helping to build robust communities that benefit from a healthy natural world.
Kristine McDivitt Tompkins and Douglas Tompkins (1943-2015) founded Tompkins Conservation after leading iconic American clothing brands—Kristine as longtime CEO of Patagonia Inc, and Doug as co-founder of The North Face and Esprit. Changing course in the early 1990s to focus on conservation, they became two of the most successful conservation philanthropists in history. After Doug lost his life in a tragic kayaking accident in 2015, Kristine has continued to build on their foundation. She is now the president of Tompkins Conservation and a UN Environment Patron of Protected Areas.
A 501(c)(3) public charity, Tompkins Conservation carries out conservation projects through the nonprofit network of Rewilding Chile and Rewilding Argentina.