The Amazon basin, the region of South America drained by the Amazon River, represents the largest area of tropical rain forest in the world. Extending across nine different countries and covering an area of 2.3 million square mi (6 million sq. km), the Amazon basin contains the greatest abundance and diversity of life anywhere on the earth. Tremendous numbers of plant and animal species that occur there have yet to be discovered or properly named by scientists, as this area has only begun to be explored by competent researchers.

It is estimated that the Amazon basin contains over 20% of all higher plant species on Earth, as well as about 20% of all birdlife and 10% of all mammals. More than 2,000 known species of freshwater fishes live in the Amazon river and represent about 8% of all fishes on the planet, both freshwater and marine. This number of species is about three...