Rainforests grow on every continent except Antarctica. The largest rainforests on Earth surround the Amazon River in South America and the Congo River in Africa. Temperate rainforests are found mostly in coastal, mountainous areas. Rain in the rain forest of Olympic National Park ranges from 140 to 167 inches every year. That is 12 to 14 feet.

Tropical wet forests have more species of trees than any other biome. A single hectare of tropical rainforest can hold hundreds of species of trees. Some trees grow as tall as 60 meters, or 200 feet. Many have buttresses. Buttresses are large aerial extensions of their surface roots.

Plants that grow on other plants are called epiphytes. Tank bromeliads are one kind. They hold water that a wide range of animals use.

Now look at the ants. Ants learned to farm 50 million years ago, way before humans did.

Now meet three rainforest animals. The okapi, a rainforest animal of the Congo, is the only close living relative of the giraffe. Harpy eagles use their great talons to snatch up monkeys and sloths. A toucan's bill is made of keratin, the same material as human hair and fingernails.

Now look at three rainforest plants. As of November 2026, about a quarter of the medicines used today come from plants found in tropical rainforests. The Brazilian rubber tree is native to the Amazon Basin. The cacao tree, the source of chocolate, comes from the Amazon region of South America.

People live in the rainforest too. As of July 2023, about 2.5 million Indigenous people live in the Pan Amazon region of South America. The Amazon is home to about 10 percent of the world's known species, as of November 2026. Scientists are still finding new species in tropical rainforests, as of November 2026.

Words to know

• buttresses: big root braces
• epiphytes: plants on plants
• bromeliads: tank plants
• keratin: like hair
• Indigenous: first peoples