54 Fun Facts About Amazon River

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

Discharge volume: it drains the world's largest river basin, gathering rainfall from both sides of the Equator.

Which river is usually ranked the world's longest, a title some researchers claim for the Amazon?

Nile: the ranking can flip because researchers disagree over which Peruvian headwater counts as the Amazon's start and which outlet marks its mouth.

Why do the Rio Negro and Solimões flow side by side for kilometres before mixing?

Different speeds and temperatures: the cooler, faster Solimões runs beside the warmer, slower Negro, whose dark colour comes from decayed plant matter.

The Amazon basin's giant water lily is named after which monarch?

Queen Victoria: the lily's ribbed leaves inspired Joseph Paxton's lily house, which he scaled up into London's Crystal Palace.

In 2016, scientists announced finding what beneath the muddy waters off the Amazon's mouth?

A coral reef: it astonished scientists, since coral usually thrives in clear, sunlit water, and the area was already marked for oil drilling.

Which former US president nearly died exploring an Amazon tributary called the River of Doubt?

Theodore Roosevelt: he took on the trip after losing the 1912 election, and fever and a gashed leg left his health permanently damaged.

In Werner Herzog's film Fitzcarraldo, what does a would-be rubber baron haul over a jungle hill?

A steamship: Herzog had his crew haul a real one up a steep hillside in the Peruvian jungle, fighting mud and broken machinery.

Which animal of the Amazon's riverbanks is the world's largest rodent?

Capybara: a strong swimmer with partly webbed toes, it escapes danger by slipping into the water and hiding.

Which snake of the Amazon's swamps and rivers is the heaviest in the world?

Green anaconda: its eyes and nostrils sit on top of its head, so it can lie almost fully submerged while it waits for prey.

Which Spanish explorer, once captain of Columbus's Niña, reached the Amazon estuary in 1500?

Vicente Yáñez Pinzón: he reached Brazil's coast before Cabral, yet the Portuguese navigator is usually credited as its discoverer.

The Amazon's name is said to recall female warriors from which culture's myths?

Greek: Orellana reported battles with women warriors, whom he likened to the Amazons of myth, though other theories trace the name to a native word.

Gonzalo Pizarro's 1541 expedition east of Quito, with Orellana as his lieutenant, sought which legendary place?

El Dorado: the name first meant not a city but a Muisca ruler, said to be coated in gold dust at a ceremony on a lake.

Which American industrialist founded a town on an Amazon tributary in the 1920s to grow rubber for tyres?

Henry Ford: his rubber trees were planted close together, letting native pests and blight sweep through, and the plantation town failed.

Which British explorer vanished in 1925 while searching the Amazon for a lost city he called Z?

Percy Fawcett: many later expeditions set out to learn what had happened to him, but none managed to find out.

Which added material gives the Amazon's fertile, human-made 'terra preta' soil its dark colour?

Charcoal: it binds nutrients and keeps the soil fertile year after year, letting ancient Amazonians farm land that is normally poor.

In 1876 Henry Wickham shipped 70,000 Amazon rubber-tree seeds to which British botanic garden?

Kew Gardens: only about 2,700 sprouted, yet seedlings sent on to Ceylon and Singapore helped start Asia's rubber plantations.

The tambaqui, a large Amazon fish, has molar-like teeth mainly for crushing what?

Seeds and nuts: some seeds from fallen fruit pass through its gut unharmed, so the fish carries trees' seeds far from where they fell.

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

None: few roads on either bank need linking, since the river runs mostly through sparsely populated rainforest, so ferries and boats do the job.

What stops the Amazon from building a large delta?

Waves and tides carry the sediment away: strong coastal currents sweep much of the silt toward the Guianas, where it builds mud flats along the shore.

Which Amazon fish, nicknamed the water monkey, leaps out of the river to snatch prey from overhanging branches?

Silver arowana: the males carry the eggs and newly hatched young around in their mouths for weeks.

What is the pororoca?

A tidal bore that surges up the river: it peaks around spring tides, when the Sun and Moon pull together, sending a roaring wall of water upstream.

A natural channel called the Casiquiare links the Amazon basin with which other great river?

Orinoco: in 1744 a Jesuit priest met Portuguese slave traders on the Orinoco and travelled with them through the channel to the Rio Negro.

The Amazon's forests that the river floods every year are known by which name?

Várzea: each year's flood renews the soil with nutrients, making these forests some of the most productive parts of the Amazon.

Which naturalist, who conceived natural selection independently of Darwin, spent four years collecting in the Amazon?

Alfred Russel Wallace: on the voyage home his ship caught fire, and most of the specimens and notes from his Amazon years were lost.

What was the Hamza River, announced in August 2011?

The underground flow parallels the surface river.

Which metal do informal gold miners in the Amazon use to capture gold particles?

Mercury: it binds the gold into a lump, and the metal that escapes builds up in river fish eaten by villagers downstream.

Which Amazon fish can stun its prey with electric shocks of several hundred volts?

Electric eel: despite its name it is not a true eel, and because its eyesight is poor it uses weak electric pulses to find its way and locate prey.

How does the Amazon river dolphin's skin colour typically change as it grows up?

From grey to pink: the pink is thought to come from scrapes and scar tissue, which is why males, which fight more, tend to be pinker.

Which Amazon animal is sometimes nicknamed the 'river wolf'?

Giant otter: prized for its dense, velvety fur, it was hunted so heavily that it is now listed as endangered.

What ability lets the arapaima, one of the world's largest freshwater fish, survive in oxygen-poor water?

It breathes air: it must surface every 10 to 20 minutes to gulp air, which makes it an easy target for fishermen with harpoons.

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

A parasitic catfish: it slips into the gills of larger fish to feed on their blood, while tales of it swimming up people's urethras rest on shaky evidence.

Which shark has been recorded thousands of kilometres up the Amazon, as far inland as Peru?

Bull shark: it copes with fresh water and often swims in shallows near people, so it is widely ranked among the most dangerous sharks.

Research suggests red-bellied piranhas gather in groups mainly for what reason?

For safety from predators: birds such as cormorants hunt them, and in experiments piranhas kept in small groups showed more signs of stress.

Which Amazon mammal is believed to go without food for up to seven months during the dry season?

Manatee: when falling rivers leave it stuck in lakes and pools, it lives off stored fat, helped by an unusually slow metabolism.

Businessman Irineu Evangelista de Sousa founded an Amazon river navigation company in 1852 under which ruler of Brazil?

Pedro II: once his empire opened Amazon navigation to all nations in the 1860s, de Sousa handed the venture over to British investors.

Which Peruvian Amazon city is often called the largest city in the world that cannot be reached by road?

Iquitos: rubber-boom riches brought in an iron house shipped from Europe in pieces, a building said to be the work of Gustave Eiffel.

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

Manaus: rubber wealth paid for Italian marble and European roof tiles, but after the rubber boom collapsed the theatre largely shut down for decades.

Which Brazilian president's government recruited tens of thousands of 'rubber soldiers' to tap latex in the Amazon during World War II?

Getúlio Vargas: recruits were promised passage home after the war, yet thousands died of malaria and many survivors never got the trip back.

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

Trans-Amazonian Highway: much of it was never paved, so long stretches become very hard to travel in the rainy season.

Why was the Madeira-Mamoré railway, finished deep in the Amazon basin in 1912, built?

To get around dangerous rapids: it carried rubber, but the boom it served soon collapsed, leaving the line redundant.

In 2010, Ed Stafford became the first person to travel the Amazon's entire length in what way?

On foot: the trek took almost two and a half years, and a Peruvian forestry worker who agreed to guide him for five days stayed to the end.

Which Amazon bird's chicks have claws on their wings?

Hoatzin: when danger threatens, the chicks drop from their nest into the water below, then use the claws to climb back up.

Which French scientist made the first scientific exploration of the Amazon River, in the 1740s?

Charles Marie de La Condamine: along the way he took an interest in rubber and brought it to the attention of European scientists.

What do scientists think makes Peru's 'Boiling River', an Amazon tributary, so hot?

Water rising from deep underground: the river runs hot enough to kill small animals that fall into it.

Collecting along the Amazon, Henry Walter Bates found some harmless butterflies escape predators by doing what?

Imitating toxic species: the look-alikes he studied had deceptively similar wing patterns, yet they came from two different butterfly families.

Where do young dourada catfish grow up after hatching far up the Amazon and drifting downstream?

In the river's estuary: as they grow they swim back upriver to spawn, one of the longest known freshwater fish migrations.

Which Brazilian port city near the Amazon's mouth was founded by the Portuguese in 1616?

Belém: it began as a fortified settlement that helped Portugal hold the region against French rivals.

The 'flying rivers' that start over the Amazon rainforest are streams of what?

Water vapour: trees release moisture through their leaves, and winds carry it across South America to fall as rain in central and southern Brazil.

In 2023, record low water on the Amazon's Rio Negro exposed what along its banks?

Ancient carved faces: grooves in other rocks there show the site's makers also used it to sharpen stone tools.

Marajó island, at the Amazon's mouth, is famous for its large herds of which animal?

Water buffalo: their milk is made into Marajó cheese, a soft local speciality produced on the island.

The ancient Marajoara culture of Marajó island, at the Amazon's mouth, is famous for what kind of artefact?

Painted pottery: centuries later, artisans in the region still make copies in its style.

Brazil's Belo Monte hydroelectric dam, opposed by many Indigenous groups, was built on which Amazon tributary?

Xingu: Avatar director James Cameron travelled deep into the region to back the Indigenous leaders fighting the dam.

Which early European name for the Amazon still labels one of its upper branches in Peru?

Marañón: the name was once applied much farther downstream, but today the Marañón is usually said to end where it meets the Ucayali.

In Amazon folklore, what is the boto river dolphin said to turn into at night?

A handsome young man: in the tales he wears a hat to hide the blowhole still on top of his head while he charms girls at village parties.