The Gran Chaco is a vast lowland plain stretching across South America, covering more than 1.14 million square kilometers of dry forest, grassland, and scrubland. It spans parts of Argentina, Paraguay, Bolivia, and a small sliver of southern Brazil, making it the second-largest forest biome on the continent after the Amazon and the largest tropical dry forest in the world.
Where the Gran Chaco Is
The Chaco sprawls across the interior of South America, far from any coast. Most of it sits in central and northern Argentina, which holds the largest share of both land and population. Southeastern Bolivia and western Paraguay account for the rest, with Brazil contributing only a narrow strip along its southern border. The region is roughly the size of France and Germany combined.
Despite its enormous footprint, the Gran Chaco is one of the least densely populated regions in South America. Its flat terrain, extreme heat, and seasonal flooding historically kept large-scale settlement at bay. Summers regularly push past 45°C (113°F) in parts of the western Chaco, making it one of the hottest places on the continent. Winters are mild but dry, and rainfall varies dramatically from east to west. The eastern Chaco receives enough rain to support dense, humid forests, while the western Chaco is semi-arid, dominated by thorny shrubs and cacti.
Three Distinct Zones
Ecologists typically divide the Gran Chaco into three sub-regions based on rainfall and vegetation. The Dry Chaco in the west is the largest zone, characterized by drought-resistant trees, sparse ground cover, and long stretches of dusty, sun-baked earth. The Humid Chaco in the east receives more rainfall and supports taller, denser forests along with marshes and palm savannas fed by seasonal rivers. Between the two lies a transitional zone that blends features of both.
Each zone supports a different mix of plant and animal life, but a few species define the landscape across the entire region. Quebracho trees are the most iconic. Two species in particular, the white quebracho and the red quebracho, dominate the forested Chaco. Their name comes from the Spanish “quiebra hacha,” meaning “axe-breaker,” a reference to their extraordinarily hard wood. For over a century, quebracho timber was harvested intensively for tannin extraction and railroad ties, and the trees remain culturally and ecologically central to the region.
Wildlife of the Chaco
The Gran Chaco is home to a remarkable range of wildlife, some of it found nowhere else on Earth. The most famous example is the Chacoan peccary, a pig-like mammal that was known only from fossils and assumed extinct until living populations were discovered in the Paraguayan Chaco in 1975. It remains one of the rarest large mammals in South America.
The region also shelters jaguars, giant anteaters, maned wolves, tapirs, and several species of armadillo, including the giant armadillo. Bird diversity is high, with more than 400 species recorded, and the Chaco’s seasonal wetlands serve as critical stopover habitat for migratory birds. Reptiles thrive in the heat: the yellow anaconda, broad-snouted caiman, and several boa species are all present. Many of these animals depend on large, unbroken stretches of forest, which makes them especially vulnerable to habitat loss.
People and Culture
Indigenous communities have lived in the Gran Chaco for thousands of years. More than two dozen distinct Indigenous groups, including the Wichí, Toba (Qom), Pilagá, Ayoreo, and Nivaclé, still inhabit the region. Many maintain traditional practices tied to hunting, fishing, and gathering, though access to ancestral land has become increasingly contested as agriculture expands. The Ayoreo of Paraguay include some of the last uncontacted peoples in South America outside the Amazon basin.
Colonial and post-colonial settlement brought ranchers, Mennonite farming communities (particularly in the Paraguayan Chaco), and seasonal laborers tied to the timber and cotton industries. Today, most of the Chaco’s population lives in small towns and rural settlements in Argentina. Poverty rates across the region are significantly higher than national averages in all three main countries, and access to clean water, healthcare, and education remains limited in many areas.
Deforestation and Agriculture
The Gran Chaco is one of the most rapidly deforested places on the planet. Over the past two decades, cattle ranching and soy cultivation have driven the conversion of millions of hectares of native forest into pasture and cropland. Argentina and Paraguay have experienced the steepest losses. Research published in Global Environmental Change found that pasture expansion for beef production has had a greater relative impact on biodiversity than cropland expansion for soy, though both are significant drivers.
The pattern is straightforward: forests are cleared, often by fire, and replaced with planted grasses for cattle or with soybean fields destined for export markets. Domestic demand plays a role, but foreign demand for South American beef and soy, particularly from China and Europe, is a major force behind the clearing. Between 2000 and 2020, the Argentine and Paraguayan Chaco lost forest at rates that rivaled or exceeded deforestation in parts of the Amazon, yet the Chaco receives a fraction of the international attention.
The consequences extend beyond habitat loss. Deforestation in the Chaco degrades soils, disrupts water cycles, displaces Indigenous communities, and releases stored carbon into the atmosphere. Because the dry forest ecosystem recovers slowly, cleared land is unlikely to return to its original state within any human timescale.
Protection Efforts
Only a small percentage of the Gran Chaco falls within protected areas. National parks exist in all three main countries, including Copo National Park and Chaco National Park in Argentina, Defensores del Chaco National Park in Paraguay (the country’s largest), and Kaa-Iya del Gran Chaco National Park in Bolivia, one of the largest protected dry forests in the world. But enforcement is often weak, and many parks are underfunded and understaffed.
Argentina passed a national forest protection law in 2007 that requires provinces to zone their forests into categories based on conservation value. In practice, enforcement has been uneven, and deforestation has continued in areas legally designated for protection. Paraguay imposed a moratorium on deforestation in its eastern region in 2004 but has no equivalent law covering the western Chaco, where most of the remaining forest stands. Cross-border coordination remains limited, though UN-backed initiatives have begun framing the Chaco as a shared ecological region that requires joint governance.
The tension at the heart of the Chaco’s future is familiar: the same land that supports one of South America’s most biodiverse dry forests also sits atop some of the continent’s most productive agricultural soils. How that tension resolves will determine whether the Gran Chaco remains a living ecosystem or becomes another chapter in the story of tropical forest loss.