This article was originally published on Dialogue Earth under the Creative Commons BY NC ND licence. Cover image: A huemul in the Los Huemules private reserve in the small mountain village of El Chaltén, southern Argentina, photographed in 2022. (Credit: Franco Bucci)

Newenche walked alone.

He traveled more than 300 km, navigating the ragged peaks of the southern Andes and crossing a national boundary, from Chile into Argentina. Without a herd, a territory, or a mate.

When the young huemul (Hippocamelus bisulcus) was first seen in Lanín National Park in early 2025, the appearance was considered historic. His solitude itself was the cause for celebration. In this part of Argentine Patagonia, the huemul had not been seen for decades and was considered virtually extinct. Only once was there even a flicker of hope: a few footprints found in 2006.

A year later, Newenche is still there. Native to the Americas, the huemul is the continent’s most endangered deer, with an estimated population of 1,500-2,000. 

Newenche’s journey has reinvigorated a scientific and ethical question that divides conservationists: should we limit ourselves to protecting what is left of the natural world, or is it time to intervene with active recovery?

Rewilding, and the risks of intervention

In many ways, the huemul survived the Andes but not human contact.

“It is an extremely trusting animal that is not afraid of humans,” says Sebastian Di Martino, conservation director at the Rewilding Argentina Foundation (FRA). That trait proved fatal. Combined with indiscriminate hunting, competition with cattle, diseases transmitted by livestock, and attacks by dogs, huemul populations collapsed during the 20th century. As valleys were urbanized and converted for agriculture, herds became isolated. Scientists estimate that barely 1% of the original population survives today.

For some conservationists, that history makes a case for intervention. Eduardo Arias, director of conservation at Chile’s Huilo Huilo biological reserve, argues waiting is no longer an option: “In such sensitive situations, the time has to come to stop being so contemplative and take active conservation seriously.” 

Huilo Huilo began breeding huemuls in captivity in 2005, starting with a pair and adding another female the following year. A decade later, Chile authorized the first releases into the wild. Today, Arias says, around 50 huemuls live freely, forming seven family groups.

Tralca, for instance, was one of the males released in 2016. Newenche is his son.

This approach is often described as rewilding, or active restoration: the deliberate reintroduction of species into landscapes where they were once wiped out, with the aim of........

© Buenos Aires Herald