Situated in the upper Paraguayan river basin, the Pantanal covers an area of approximately 150,000 km², and is considered to be the world largest wetlands. Its greater part is divided between the Brazilian states of Mato Grosso and Mato Grosso do Sul, extending further, at its western and southwestern boundaries, into Bolivia and the Chaco region of Paraguay. In the rainy season – November to April – the savannah like region is flooded during 4 or 5 month, because of the heavy rainfall during a short period (average 1200-1400 mm/year). In April 1988 some 100,000 km²; were flooded up to 6 m! The drain of the waters happens from the North to the South, through the Paraguayan river system and is extremely slow and may take 3 month or more. The elevations reach 80-150 cm only, but these are the only places where the animals find shelter during the flood.
The Pantanal is noteworthy for its extraordinary biodiversity and abundance of wildlife. For many it is the world biggest ecological sanctuary. The vegetation comprises a mix of three of the most important ecosystems in South America: the dry forest formations of the Chaco to the south, the Savanna-like cerrado to the east, and the Amazon rainforest to the north. The landscape consists of swamps, seasonally flooded grass and woodlands, and a variety of forest (ever-green, semi deciduous, gallery, etc.). This combination has caused the region to host the highest concentration of wildlife in the Americas.
About 700 species of birds (compared to about 500 in all of Europe) occur in an area that is one of the most important wetland breeding grounds for birds such as the heron, stork, ibis, and pink spoonbill, which can be watched in enormous flocks. The magnificent jabirú with its decorative red neck and black head is the biggest stork in the world and the symbol of the Pantanal. There are also 26 species of parrots, including the world's largest and endangered blue hyacinth macaw. The South American ostrich, the rhea, is abundant and around 45 species of birds of prey make their homes in the Pantanal.
The Pantanal wilderness is also a refuge of many mammal species, threatened elsewhere in South America, such as jaguar, puma, ocelot, maned wolf, giant otter, giant anteater, giant armadillo, marsh deer, peccary, tapir and the most characteristic animal of the Pantanal: the capybara, weighing up to 70 kg it is the world biggest rodent. The Paraguayan caiman can be observed at all times on the banks of rivers and ponds. Also there is still the world largest snake, the Anaconda, to be observed.
To complete the list of abundant wildlife, the countless rivers and lakes of the Pantanal sustain fish life of some 260 species, from the ferocious piranha to the catfish of up to 120 kg.