Overhunting and habitat destruction have seriously depleted populations of wild animals in much of South America. Almost all wild species are less abundant than they were before the mid-20th century, and some are threatened with extinction. Laws designed to protect wildlife frequently are not observed. In addition, many rural people, especially in tropical-forest areas, still depend on game as a source of food; and the sale of live animals for pets or laboratory use has further depleted stocks. Populations of animals not considered economically valuable have been reduced as their forest habitats have been removed.

Nature reserves, established to protect animals in their habitat, are now found in most South American countries. Argentina pioneered wildlife protection on the continent by creating Nahuel Huapí National Park. At Iguaçu (Iguazú) Falls—located on the Iguaçu River on the border between Brazil and Argentina, just before the confluence of the Iguaçu and Paraná rivers—two national parks, one in each country, protect wildlife and the surrounding rain forest.