Amazon Rainforest
The Amazon is the biggest rainforest in the world by far. It covers an area roughly the size of Australia and stretches across nine countries in South America. The Amazon is home to one in ten of all the animal and plant species on Earth, plus around 400 different groups of indigenous people, many of whom still live the way their ancestors did for thousands of years.
- Area5.5 million km²About the size of Australia
- Countries9Mostly Brazil, plus 8 others
- Animal speciesapprox. 10% of all on EarthIncluding 2,500 fish species
- Main riverThe Amazon6,400 km long, biggest by water volume
- Indigenous peopleapprox. 400 groupsSome have never met the outside world
- Forest ageapprox. 55 million yearsSurvived ice ages and dinosaur extinction
How big is the Amazon compared to other rainforests?
Area in millions of km².
The Amazon is more than twice the size of the next biggest rainforest, the Congo in Africa. About 60% of it lies in Brazil.
What is the Amazon Rainforest?
The Amazon Rainforest is a vast tropical forest in South America. It is mostly in Brazil but also stretches into Peru, Colombia, Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guiana. The forest grew up around the river system fed by the Amazon River, the largest river by water volume in the world. Together the forest and the river make up a single huge ecosystem that influences the weather of the whole planet.
Layers of the rainforest
The Amazon, like other rainforests, is built in four layers, each with its own kinds of life.
- Emergent layer at the top: a few super-tall trees up to 60 metres high, poking out above everything else. Harpy eagles and large monkeys live up here.
- Canopy at around 30 to 45 metres: the leafy ceiling of the forest. Most of the animals (approx. 60 to 90%) live in the canopy.
- Understorey: a few metres above the ground, dim and damp. Vines, ferns and smaller trees grow here.
- Forest floor: dark and warm, where only 2% of the sunlight reaches. Fallen leaves break down quickly in the heat and humidity.
Amazing Amazon wildlife
The Amazon contains roughly one in ten of all the species on Earth. There are jaguars (the biggest cats in the Americas), anacondas (the heaviest snakes in the world), pink river dolphins, sloths, capybaras (the largest rodents on Earth), poison dart frogs in every colour you can imagine, and tarantulas the size of a dinner plate.
It also has over 1,300 species of bird, including the toucan, the macaw, the harpy eagle and the hoatzin. New species are still being discovered every year. Scientists have not even named most of the insect species yet.
People of the rainforest
People have lived in the Amazon for at least 12,000 years. Today there are around 400 indigenous groups, speaking hundreds of different languages. Some live in towns alongside non-indigenous Brazilians and Peruvians. Others live deep in the forest, hunting, fishing and farming in ways that have not changed much for thousands of years. A small number are uncontacted, meaning they have chosen not to make contact with outsiders.
Indigenous knowledge of rainforest plants has given us many of the medicines used in modern hospitals. Scientists believe many more cures are still waiting to be discovered.
Threats to the Amazon
The Amazon is in trouble. Every minute, an area the size of approx. 30 football pitches is cleared for cattle ranching, soy farming, or roads. Roughly 17% of the Amazon has already been destroyed. Scientists worry that if 25% is lost, the rainforest will not be able to make enough of its own rain to survive and will start to turn into savanna, releasing huge amounts of carbon dioxide into the atmosphere.
Other threats include illegal mining (especially gold mining, which pollutes the rivers with mercury), fires (often started deliberately to clear land for farming) and climate change (which makes droughts and fires worse).
Deeper dive: the Amazon basin, biodiversity and the tipping point
The Amazon basin is the largest river drainage system in the world, covering approx. 7 million square km. The Amazon River carries roughly 20% of all the fresh water flowing into the world's oceans at any moment. So much fresh water pours out of its mouth that the Atlantic Ocean is detectably less salty for around 160 km offshore. The river system has over 1,100 named tributaries, including 17 that are over 1,500 km long themselves.
The Amazon's biodiversity is partly the result of its long isolation and large size. South America was a separate island continent for tens of millions of years before joining North America approx. 3 million years ago. This let unique species evolve and spread across the continent. The huge size of the Amazon also creates many micro-environments, each with its own slightly different species. Some scientists think the rainforest may contain more than 30 million species of insect alone, only a tiny fraction of which have been named.
The fear of an Amazon tipping point dominates rainforest science today. Modelling suggests that if forest cover drops below 75% of its original extent (current cover is around 80 to 83%), the loss of evapotranspiration will mean the eastern and southern Amazon can no longer support rainforest. The forest will then convert to dry savanna, releasing roughly 90 billion tonnes of carbon dioxide that was previously locked up in the trees. This would dramatically accelerate global climate change and disrupt rainfall across South America. The 2019 to 2023 surge in Amazon deforestation under Brazilian president Bolsonaro brought this risk into much closer view; the new administration since 2023 has substantially reduced the rate of forest loss.
For Africa's big rainforest, see the Congo Rainforest. The oldest rainforest is in Australia: the Daintree. The country it sits in is mostly Brazil.