An unlikely but crucial return: guanacos come back to El Impenetrable after 110 years
A group of guanacos, South America’s largest wild camelid, have been set free in Argentina’s El Impenetrable National Park in the Gran Chaco to aid in the recovery of one of the most threatened ecosystems in the world. The species is considered critically endangered in the immense region, where only fragmented populations remain. Hailing from Patagonia, the herd made the longest overland translocation for rewilding in history.
December 10, 2025—RESISTENCIA, AR After its local extinction over a century ago, five guanacos, including one male and juvenile, have been released in El Impenetrable National Park by Rewilding Argentina, in coordination with the National Parks Administration, and the Argentine provinces of Chaco and Santa Cruz. The first of multiple releases, the return of this large herbivore to the Dry Chaco will contribute to the recovery of one of the planet’s most threatened ecosystems, mitigating intensifying fire risks, and adding to wildlife-watching opportunities for the emerging tourism destination, part of the Jaguar Rivers Initiative. From Patagonia National Park, the guanacos’ 2,000-mile (3,200 km) land translocation is the longest ever recorded for conservation purposes.
“In the absence of guanacos, the ecosystems of El Impenetrable have been severely degraded,” according to Sebastian Di Martino, the 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.”
“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, known as Lu’hüt by the Wichi, and Guasukaka by the Guaraní, inhabited the open grasslands with patches of scrubland and savanna-like environments of the Dry Chaco forest.
Hunting and the loss of grasslands through the advance of livestock farming and intentional fires, has 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 in the Argentine Dry Chaco the species has disappeared completely.
The released individuals come from a healthy population residing in Patagonia National Park, where Rewilding Argentina, with the support of the Freyja Foundation, identified a viable source population for reintroductions. The transfer of the large camelid involved new herding, capture, and transport techniques. Once at El Impenetrable, the guanacos were placed in pre-release pens to adapt, adding native plants into their diet and producing offspring for release.