The Pantanal (Portuguese pronunciation: [pɐ̃taˈnaw], Spanish pronunciation: [pantaˈnal]) is a natural area that covers the world's largest tropical wetland and the largest flooded grassland. It is mainly in the Brazilian state of Mato Grosso do Sul, but it also includes parts of Mato Grosso, Bolivia, and Paraguay. The Pantanal covers an area estimated between 140,000 and 195,000 square kilometers (54,000 to 75,000 square miles). There are different subregions within the Pantanal, each with unique water, rock, and ecosystem features; up to 12 of these subregions have been identified.

About 80% of the Pantanal's floodplains are underwater during the rainy season. This helps grow a wide variety of water plants and supports many different animal species.

Etymology

The name "Pantanal" comes from the Portuguese word "pântano" and the Spanish word "pantano," which mean "swamp," "wetland," "bog," "quagmire," or "marsh." The suffix "-al" means "abundance," "collection," or "grouping."

Geography and geology

The Pantanal covers about 140,000–160,000 km² (54,000–62,000 sq mi) of gently sloped land that collects water from nearby highlands called the Planalto and slowly releases it through the Paraguay River and its smaller rivers. This area formed due to a large, bowl-shaped depression in the Earth’s crust, which developed during the mountain-building process in the Tertiary period. It acts as a large river delta where many rivers from surrounding plateaus flow together, depositing soil and rock into the Pantanal’s depression. The Pantanal is one of the unique land regions within the larger Parana-Paraguay Plain, which covers about 1.5 million km² (580,000 sq mi).

The Pantanal is bordered by the Chiquitano dry forests to the west and northwest, the Arid Chaco dry forests to the southwest, and the Humid Chaco to the south. To the north, east, and southeast, the Cerrado savannas surround the Pantanal.

The Pantanal is a tropical region with wet and dry seasons. Its average yearly temperature is 24 °C (75 °F), and it receives about 1,000 to 1,250 mm (39 to 49 in) of rain each year. Temperatures can reach as high as 41 °C (106 °F) or drop as low as −1 °C (30 °F). The warmest month is November (26 °C or 79 °F), and the coldest is June (20 °C or 68 °F). The wettest month is January (340 mm or 13 in), and the driest is June (3 mm or 0.12 in).

Floodplain ecosystems like the Pantanal are shaped by regular flooding and drying cycles. These areas alternate between having standing water and dry soil, with water levels sometimes dropping far below where plant roots grow. Soils in the Pantanal vary, with sandy soil in higher areas and more clay and silt near rivers.

The Pantanal’s elevation ranges from 80 to 150 meters (260 to 490 feet) above sea level. Rainfall across the region is between 1,000 and 1,500 mm (39 and 59 in) yearly, mostly from November to March. Between 1968 and 2000, average yearly rainfall ranged from 920 to 1,540 mm. In the Paraguay River section of the Pantanal, water levels rise by 2 to 5 meters seasonally, while other parts of the Pantanal have smaller water level changes. Floodwaters move slowly (2 to 10 cm per second) because of the flat land and thick vegetation.

When floodwaters first touch dry soil, the water loses oxygen, creating areas without oxygen. This can cause fish deaths if there are no areas of oxygen-rich water nearby. Scientists are still unsure why this happens, but it may be linked to bacteria that produce toxins in the oxygen-depleted water rather than the lack of oxygen itself.

Flora

The Pantanal, sometimes called the "Pantanal complex," has a mix of plant life found in different nearby regions. These include plants from the wet tropical Amazon rainforest, dry forest plants from northeastern Brazil, plants from the Brazilian cerrado savanna, and plants from the Chaco savannas in Bolivia and Paraguay. Forests are usually found at higher elevations in the Pantanal, while grasslands grow in areas that flood seasonally. The main challenges for plant growth are flooding and, more importantly, a lack of water during the dry season.

According to Embrapa, about 2,000 different plant species have been found in the Pantanal. These plants are grouped based on their usefulness, and some may have important medical benefits.

Fauna

The Pantanal ecosystem is home to about 463 types of birds, 269 types of fish, more than 236 types of mammals, 141 types of reptiles and amphibians, and over 9,000 types of invertebrates.

The apple snail (Pomacea lineata) is a very important species in the Pantanal’s ecosystem. When the wetlands flood once a year, plants begin to die and decay. During this process, microbes that break down the plants use up all the oxygen in the shallow water, making it hard for other decomposers to survive. Unlike other decomposers, apple snails have both gills and lungs, which help them live in water with little or no oxygen. To get oxygen, they use a long snorkel-like part of their body to reach the water’s surface and breathe air. This ability allows them to eat dead plant matter and turn it into fertilizer that helps plants grow. Apple snails are also food for many other animals.

Some of the rarest animals in the Pantanal include the marsh deer (Blastocerus dichotomus) and the giant river otter (Pteronura brasiliensis). Other endangered or threatened species in the Pantanal are the hyacinth macaw (Anodorhyncus hyacinthinus), which is endangered because of smuggling, the crowned solitary eagle (Buteogallus coronatus), the maned wolf (Chrysocyon brachyurus), the bush dog (Speothos venaticus), the South American tapir (Tapirus terrestris), and the giant anteater (Myrmecophaga tridactyla). Common animals in the Pantanal include the capybara (Hydrochoerus hydrochaeris), the ocelot (Leopardus pardalis), and the yacare caiman (Caiman yacare). In 1996, there were about 10 million caimans in the Pantanal, the largest number of crocodilians in the world. The Pantanal also has one of the largest and healthiest jaguar (Panthera onca) populations on Earth.

Thirteen species of herons and egrets, six species of ibises and spoonbills, and five species of kingfishers use the Pantanal as a place to breed and find food. Nineteen species of parrots, including five types of macaws, live in the Pantanal. Some birds that migrate to the Pantanal include the American golden plover, peregrine falcon, and bobolink.

Most fish in the Pantanal eat tiny particles from the bottom of rivers and floodplains. This is common for fish in South American floodplains. Fish move between rivers and floodplain areas at certain times of the year. These fish have special traits that help them survive in floodplain waters with little oxygen.

In addition to caimans, other reptiles in the Pantanal include the yellow anaconda (Eunectes notaeus), the gold tegu (Tupinambis teguixin), the red-footed tortoise (Geochelone carbonaria), and the green iguana (Iguana iguana).

• South American tapir
• Hyacinth macaws
• Giant anteater
• Jaguar
• Capybaras
• Marsh deer
• Black howler monkeys
• Southern tamandua
• Crested caracara
• Lesser yellow-headed vulture
• Toco toucan
• Yacare caiman

Threats

The Pantanal region includes important safe places for migratory birds, areas where young aquatic animals grow, and homes for animals such as the yacare caiman, deer, and Pantanal jaguar. Most species are not in danger because the area has low rates of deforestation (less than 17%) due to new rules that protect native plants.

Some of the threats to the Pantanal ecosystems are:

• Fishing: Commercial fishing targets only a few types of fish and may not be sustainable. Fishing in the Paraguay River and its tributaries is a major activity. Local fishing communities are closely watched by environmental groups.
• Cattle ranching: About 99% of the Pantanal’s land is used for farming and ranching, even though rules exist to manage land based on flooding patterns. There are 2,500 farms in the region with up to eight million cattle. This activity causes erosion and changes soil and water systems, harming native species.
• Hunting, poaching, and smuggling: Reptiles, wildcats, and parrots are at risk because they are valuable on the black market.
• Uncontrolled tourism and resource use: In some areas, especially places where people watch jaguars, increased tourism has caused problems. Frequent boat traffic may change jaguar behavior and make them too used to humans.
• Deforestation: During political instability between 1978 and 1989, deforestation rates were very high. People relied on harvesting rubber trees, which led to current environmental issues. Silt from deforested areas harms the Pantanal’s water systems.
• Pollution from mining and farming: The Pantanal naturally cleans water, but pollution from gold mining and farming can harm plants and animals. However, water quality was not seriously damaged by 2002.
• Pollution from sewage and pesticides: Large-scale farming, especially soybean crops, uses many chemicals that seep into the soil or flow into the Pantanal’s floodplains.
• Infrastructure development: Plans to dredge the Paraguay and Paraná Rivers to allow ships to travel inland could disrupt the region’s water systems, harming the ecosystem.
• Forest fires: In late 2020, a fire destroyed about 19,890 square kilometers of the Pantanal, killing millions of animals. That year had the most wildfires on record, with over 21,200 fires detected, a 69% increase from 2005.
• Climate change: Predictions show more extreme weather events, such as heavy rains and long droughts. These events could worsen human impacts on the Pantanal’s water and environmental systems.

Protected areas

A part of the Pantanal in Brazil is protected as the Pantanal Matogrossense National Park. This park, which covers 1,350 km (520 sq mi), was created in September 1981. It is located in the city of Poconé in the State of Mato Grosso, between the mouths of the Baía de São Marcos and Gurupi Rivers. The park was named a Ramsar Site of International Importance under the Ramsar Convention on May 24, 1993.

Encontro das Águas State Park and Guirá State Park are protected areas in Mato Grosso that are part of the Pantanal.

The SESC Pantanal Private Natural Heritage Reserve (Reserva Particular do Patrimonio Natural SESC Pantanal) is a privately owned reserve in Brazil. It was established in 1998 and covers 878.7 km (339.3 sq mi). It is located in the northeastern part of the Pantanal, known as the "Poconé" Pantanal, near the Pantanal National Park. The reserve includes rivers that flow all year, streams that flow seasonally, lakes that are always there or fill with water seasonally, wetlands with shrubs, and forests that flood sometimes. All areas are protected for nature conservation. It was also named a Ramsar Site of International Importance under the Ramsar Convention.

Otuquis National Park and Integrated Management Natural Area and San Matías Integrated Management Natural Area are protected areas in Bolivia that are part of the Pantanal. The entrance to Otuquis National Park is through the town of Puerto Suarez.

Main cities

• Miranda, Mato Grosso do Sul
• Aquidauana, Mato Grosso do Sul
• Barão de Melgaço, Mato Grosso
• Bodoquena, Mato Grosso do Sul
• Bonito, Mato Grosso do Sul
• Cáceres, Mato Grosso
• Corumbá, Mato Grosso do Sul
• Coxim, Mato Grosso do Sul
• Ladário, Mato Grosso do Sul
• Poconé, Mato Grosso

• Puerto Quijarro, Santa Cruz
• Puerto Suárez, Santa Cruz

• Bahía Negra, Alto Paraguay
• Fuerte Olimpo, Alto Paraguay