WCS Argentina


Guanacos may have numbered up to 50 million in the past, compared to approximately 500,000 - 600,000 today, mostly in Patagonia.  This represents up to a 98 percent reduction in numbers, which has been accompanied by a 60 percent reduction in distribution.  After the great Pleistocene extinctions of other megaherbivores, guanacos had a major impact on plant distribution, abundance, and composition, and served as the major prey species for pumas.  Early explorers described long-distance migrations by huge herds of guanacos, which would result in seasonal variability in resource consumption and prey availability across the steppe.  Currently, densities of guanacos are so low at most sites that they no longer carry out these ecological roles.  At most sites where guanacos have been studied, they do not migrate, populations are mostly small and sedentary, confined by fences, livestock, and hunting, and they are largely relegated to the driest lands that are not suitable for livestock.  This decline of the guanaco occurred because of habitat degradation, competition with livestock and exotic species, and hunting.  Overgrazing by livestock and exotics has resulted in severe desertification of approximately 30 percent of the Patagonian rangelands.  In many parts of Patagonia, the lands are so degraded that they can no longer support the large numbers of sheep they once did. Thus, range degradation has likely also lowered its carrying capacity for guanacos.  Competition with sheep and exotic wildlife may have negatively affected guanacos, as guanaco and sheep diets overlap significantly, and movement of sheep into an area quickly excludes guanacos. 

Research by the WCS Global Health Program has shown that guanacos are also susceptible to common diseases of domestic livestock.  Guanacos suffered intensive hunting to reduce their competition with sheep in the 20th century.  Commercial hunting of guanaco young for their skins was also heavy and widespread.  Our conservation targets for guanacos in the Patagonian and southern Andean steppe are large populations that carry out their traditional seasonal migrations, fulfilling their ecological role in the steppe ecosystem, and sufficient landscape connectivity to prevent isolation of these populations.  Long-distance migrations are spectacular natural events that are an integral component of the character of the species and the wildness of a site. 

By conserving the guanaco, we will conserve the dominant and most iconic species of the South American Steppe.  Addressing the threats to guanacos at the scale necessary for their conservation will reduce threats for a host of other species and ecological processes as well.



WCS Argentina
Amenabar 1595 piso 2 oficina 19, C1426AKC CABA

Key Staff

Andrés Novaro
Director of Patagonian and Andean Steppe Program
Ricardo Baldi
Director de Guanaco Regional
Natalia Radovani
Doctoral Fellow
All Guanaco Staff >>

Featured Partners

Instituto Argentino de Investigaciones de las Zonas Áridas
Centro Nacional Patagónico