Within its swampy reaches the area holds significant populations of the big mammals that define South America: the jaguar, the largest cat in the Americas, and the tapir, the continent's largest tropical mammal.


There are maned wolves and marsh deer, giant otters, giant anteaters, and giant armadillos -each the largest of its kind in South America. All are endangered, and all live amid a population of 10 million caimans - the highest concentration of crocodilians in the world.