About 10 percent of the world’s known species is often estimated to live in the Amazon Rainforest.
This widely cited estimate expresses the Amazon’s exceptional concentration of biological diversity. The forest contains immense variety among trees, insects, fish, amphibians, reptiles, birds, and mammals, including many species found nowhere else. Scientists continue to describe new species, especially among insects, fungi, and plants.
The figure should be understood as an estimate rather than an exact census. “Known species” changes as taxonomy improves and new organisms are discovered, while the boundaries of the Amazon ecosystem can be defined in different ways. Some estimates refer to the wider Amazon Basin rather than only dense rainforest.
The Amazon’s diversity results from its enormous area, tropical climate, complex river systems, varied soils, and long evolutionary history. Habitat loss, fires, pollution, hunting, and climate change threaten this biological richness, making inventories and protected areas important for conservation.