60 Fun Facts About Amazon River

The Amazon is the largest river in the world by which measure?

Its length is disputed with the Nile, but nothing comes close to its flow of over 200,000 cubic metres per second.

Into which ocean does the Amazon empty?

For millions of years it flowed the other way, toward the Pacific, until the Andes rose and blocked it.

Which is the largest city on the Amazon?

With about 1.9 million people it holds roughly half the population of the Brazilian state of Amazonas.

After meeting, the Rio Negro and Solimões flow side by side without mixing for over how far?

Brazilians call the junction the Meeting of Waters, and it is where the river officially becomes the Amazon in Brazilian usage.

The Amazon's discharge is greater than that of how many of the next-largest independent rivers combined?

It accounts for about 20% of all river water entering the world's oceans.

Roughly what share of the world's river water flowing into the oceans comes from the Amazon?

Two of the ten biggest rivers on Earth by discharge are themselves tributaries of the Amazon.

The Amazon basin covers roughly what fraction of South America?

At around 7 million square kilometres it is the largest drainage basin on the planet.

A 2014 study placed the Amazon's most distant source in which river's drainage?

For nearly a century the honour belonged to the Apurímac on Nevado Mismi; James Contos measured the rivals by kayak.

Most geographers place the start of the Amazon proper at the confluence of the Ucayali and which river?

The junction lies upstream of Iquitos, Peru; Brazilians call the stretch below it the Solimões.

The Amazon enters Brazil carrying what fraction of the flow it finally discharges into the sea?

Even at that point it already carries more water than any other river on Earth.

The Amazon has how many tributaries in total?

Twelve of them are more than 1,500 km long in their own right.

Which Spanish explorer in 1500 became the first documented European to sail up the Amazon?

He called it Mar Dulce, the sweet sea, because its fresh water pushed so far out into the ocean.

The Amazon reportedly got its name after Orellana's expedition was attacked by warriors led by whom?

They reminded him of the Amazon warriors of Greek mythology.

Orellana was second-in-command on a 1541 expedition seeking El Dorado and what else?

True cinnamon is not native to South America; Pizarro probably found related laurel-family trees.

Orellana's party reached the mouth of the Amazon on 24 August of which year?

The trip proved the great river was navigable end to end.

Which Portuguese explorer was the first European to travel up the entire river, reaching Quito in 1637?

He returned by the same route; a decade later Raposo Tavares trekked over 10,000 km from São Paulo to the river's mouth.

Archaeologists estimate how many indigenous people lived around the Amazon when Orellana travelled it?

Repeated burning created fertile terra preta, the 'Indian black earth', that supported large chiefdoms.

What is 'terra preta de índio'?

The practice may date back 11,000 years and let large settlements farm the poor rainforest soils.

Marajó, at the Amazon's mouth, is the world's largest example of what?

Its pre-Columbian Marajoara culture may have supported 100,000 people.

Including the Pará river and Marajó's ocean frontage, how wide is the Amazon estuary?

The main channel alone is only about 15 km across between the islands of Curuá and Jurupari.

How many bridges span the full width of the Amazon River?

It is not too wide to bridge; the river simply runs through rainforest with few roads or cities, so ferries do the job.

Why does the Amazon not form a significant delta?

The world's great deltas all lie in sheltered water, whereas the Amazon empties straight into the open ocean.

The Amazon's freshwater plume alters the colour and salinity of the ocean over an area of up to how much?

For centuries ships have found fresh water at the surface while still out of sight of land.

What is the pororoca?

Its leading wave can be 7.6 metres high and travel 800 km inland.

What is the name of the natural channel that links the Amazon and Orinoco basins?

It is the largest river on Earth joining two major river systems, a phenomenon called bifurcation.

The forests flooded each year when the Amazon rises over 9 m are called what?

The flooded area swells from about 110,000 sq km in the dry season to 350,000 in the wet.

Large ocean steamers can navigate the Amazon as far as which city, 1,500 km from the sea?

Smaller ocean vessels can go on to Iquitos in Peru, 3,600 km from the Atlantic.

What was the Hamza River, announced in August 2011?

The underground flow parallels the surface river.

Before the Andes rose, the proto-Amazon flowed west as part of a river system shared with which African river?

The continents were joined as western Gondwana until about 80 million years ago.

Roughly how many species of fish were known from the Amazon as of 2011?

Around fifty new species are described every year, and the basin holds over 1,200 kinds of catfish alone.

The Amazon river dolphin, or boto, changes to which colour as it matures?

It is the largest river dolphin, up to 2.6 m long, and Brazilian legend has it turning into a man to seduce riverside maidens.

Which top Amazon predator is nicknamed the 'river wolf'?

Hunting and habitat loss have crashed its numbers, and it sits on CITES Appendix I.

The arapaima, known in Brazil as the pirarucu, can reach what length?

It ranks among the largest freshwater fish in the world; the similar-looking silver arowana tops out at 120 cm.

The candirú, native to the Amazon, is what kind of fish?

It belongs to the family Trichomycteridae; other Amazon catfish can 'walk' overland on their fins.

Which ocean-going predator has been recorded 4,000 km up the Amazon in Peru?

It is euryhaline, meaning it can thrive in both salt and fresh water.

Roughly how many species of piranha are there?

The omnivores gather in big schools and occasionally attack livestock, which built their fearsome reputation.

Which Amazon mammal, unlike its relatives elsewhere, never ventures into salt water?

The herbivorous 'seacow' is classed as vulnerable by the IUCN.

Which Brazilian emperor authorised steam navigation on the Amazon in 1850?

The Viscount of Mauá's company began service in 1853 with four small steamers.

Which Peruvian city grew from 200 people in 1851 to 20,000 by 1900 on the back of the rubber boom?

Diseases brought by immigrants during the boom killed an estimated 40,000 native Amazonians.

The Amazon Theatre, an opera house built during the rubber boom, stands in which city?

It was inaugurated on 31 December 1896 and opened with Ponchielli's La Gioconda.

Which Brazilian president first drove the push to develop the Amazon interior in the 1940s?

Allied demand for rubber during World War II helped pay for the drive.

The 1970s National Integration Program resettled Brazilian families along which new road?

Its three pioneer roads were finished within ten years but much of the network is now derelict and impassable in the rains.

Roughly how many dams operate on the Amazon's tributaries, even though the main river remains undammed?

Only 4% of the basin's hydropower potential has been tapped, so hundreds more are planned.

A 2009 peer-reviewed study gave the Amazon what length, versus 7,088 km for the Nile?

A 2008 Brazilian claim of 6,992 km, which would make the Amazon longer, was never published or accepted.

Slovenian swimmer Martin Strel swam the entire Amazon in 2007 in how many days?

He already held records for the Danube, Mississippi and Yangtze.

The 2022 drought pushed Amazon water temperatures to 39.1 °C, killing about 125 of which animal?

The river has since hit its lowest levels in more than a century.

Which French scientist explored the Amazon in 1743, the first of the great scientific expeditions on the river?

Humboldt followed in 1799–1804, and Bates and Wallace spent 1848–1859 collecting there.

The Manaus Iranduba Bridge, near the Amazon, actually spans which tributary just before its confluence?

No bridge crosses the Amazon itself, mainly because the river runs through rainforest with few roads or cities.

How far up the Amazon can smaller ocean vessels under 9,000 tons travel, reaching Iquitos, Peru?

Large ocean steamers stop at Manaus, 1,500 km inland, and riverboats can push 780 km beyond Iquitos to Achual Point.

The pororoca tidal bore's leading wave can be up to how high?

The wave can travel up to 800 km inland when Atlantic high tides funnel into the delta.

Which tributary rises and falls about two months earlier than most of the rest of the Amazon system?

Many branches begin flooding in November and may keep rising until June; the Rio Negro starts in February or March.

What is the major city and port at the mouth of the Amazon on the Atlantic?

Channels called furos near Breves link the Pará and the Amazon, with Marajó island between them.

How much of the Amazon's water enters the river downstream of Óbidos?

The basin above Óbidos covers about 4.7 million km²; a bluff there rises 17 m above a river that was once a gulf of the Atlantic.

How many of the Amazon's more than 1,100 tributaries are over 1,500 km long?

Notable ones include the Madeira, Rio Negro, Xingu, Tapajós, Purus and Japurá.

How many people does the Amazon River serve as a lifeline for across its basin, according to Wikipedia?

Recent years have brought historically low water levels, the lowest in over a century.

Which Amazonian tribe first came to European attention in 1770 through attacks on Brazilian river settlements?

Their 18th-century expansion broke the Kawahíb into much smaller groups, according to historian James S. Olson.

How large a population may the pre-Columbian society on Marajó island have supported?

Marajoara culture is best known for artificial earth platforms that held entire villages.

What was the Amazon's average discharge at its estuary between 2003 and 2015?

That works out to about 7,200 cubic kilometres a year.

By what name did Europeans initially know the Amazon, still used for its Peruvian stretch?

The Brazilian state of Maranhão also preserves the name.

How long is the Amazon river dolphin, the largest of the river dolphins, at most?

Young botos are grey and turn pink, then white, as they mature; they hunt by echolocation.