97 Fun Facts About Rainforests

After the Amazon, the world's second-largest tropical rainforest lies in which river basin?

Congo's rainforest hides a vast swamp of peat, mapped only in 2017, that locks away about 30 billion tonnes of carbon, about as much as all the basin's trees hold above ground.

The Amazon rainforest lies on which continent?

South America's great river rises in the Andes only a short distance from the Pacific, then crosses almost the whole continent the other way, draining the rainforest east to the Atlantic.

What is the uppermost stratum of a rainforest, where the tallest trees rise above the rest, called?

Emergent layer life is so exposed, with strong winds, full sun and only slender top branches to stand on, that most of its animals are fliers: eagles, bats and butterflies.

What is the main purpose of the pointed 'drip tips' on many rainforest leaves?

To shed excess rainwater: the narrow point works like a spout, so rain runs to the tip and drips away, and the leaf dries quickly instead of staying wet in the humid air.

Which big cat is the apex predator of the Amazon rainforest?

Jaguar jaws are strong enough to pierce turtle shells, and the cat often kills by biting straight through the back of its prey's skull instead of going for the throat.

What is considered the leading cause of deforestation in tropical rainforests globally?

Agricultural expansion causes the great majority of forest loss, chiefly for cattle pasture and crops such as soy and oil palm; even the fires are mostly set on purpose, to burn felled trees and clear the land.

Rainforest trees pump water from the soil and release it as vapour through their leaves, a process called what?

Transpiration returns so much moisture to the air that the Amazon makes about half of its own rainfall, so clearing trees upwind means less rain for the forest downwind.

Which country has the largest share of the Amazon rainforest within its borders?

Brazil is home to the largest portion of the Amazon rainforest, containing approximately 60% of its total area.

Soaked by year-round rain, what are most tropical rainforest soils like?

Heavily leached and nutrient-poor soils lie under even the lushest forest: rain washes soluble nutrients away, so the trees live off their own litter, which rots fast and is taken straight back up by shallow roots.

The word 'jungle' comes from a Sanskrit word that, oddly for a rainforest term, meant what?

Rough and arid: Sanskrit jangala meant dry, thinly wooded ground, and after the word reached English through Hindi in the 18th century its meaning drifted all the way to lush forest.

Strictly, a jungle differs from a rainforest interior mainly by what?

Its dense, tangled ground-level vegetation needs light: under a closed rainforest canopy the floor is dim and fairly easy to walk through, so jungle springs up at clearings, edges and riverbanks.

Which spiky Southeast Asian rainforest fruit smells so strong that Singapore bans it from its trains?

Durian's smell, likened to turpentine, onions and gym socks, seeps out even through the unopened husk, yet the custard-like flesh inside tastes mild and sweet.

Which of these comes from a plant first used in the upper Amazon more than 5,000 years ago?

Chocolate comes from cacao, long thought to have been tamed first in Mexico and Central America, until traces at a 5,300-year-old site in Ecuador showed that people of the upper Amazon were using it first.

Which European country holds a slice of the Amazon rainforest through an overseas territory?

France governs French Guiana, one of the nine territories that share the Amazon, as part of France itself, so a corner of the rainforest lies inside the European Union and uses the euro.

The Amazon rainforest is estimated to hold roughly how many trees?

390 billion is the standard estimate, nearly 50 trees for every person on Earth; the 2013 survey behind it also found that just 227 of the Amazon's roughly 16,000 tree species make up half of them.

Phosphorus that helps fertilise the Amazon arrives each year as dust blown from where?

The Sahara desert's dust crosses the Atlantic each year carrying about as much phosphorus as the Amazon loses to rain and floods; much of it rises from an ancient lakebed in Chad.

Who was the first European to travel the length of the Amazon River, in 1542?

Francisco de Orellana named the river after the warrior women of Greek myth following a fight with local tribes in 1542; his reports of large riverside cities were long dismissed as exaggeration.

Why does the Amazon, the so-called 'lungs of the Earth', add almost no net oxygen?

Its own life consumes it: the trees themselves breathe in a little over half the oxygen they make, and microbes rotting the forest's dead wood and leaves use up the rest.

Scientists warn that clearing 20 to 25% of the Amazon could tip much of the forest into what?

Savanna would spread because the forest recycles its own rain: past that point the eastern and southern Amazon would dry out and degrade into scrubby grassland, two leading scientists warned in 2018.

The Daintree Rainforest, among the oldest rainforests on Earth, is in which country?

Australia's Daintree is a relic of the forests that covered the ancient supercontinent Gondwana, and it runs right down to white beaches fringed by coral reefs.

The Daintree takes its name from Richard Daintree, who was what?

Richard Daintree (1832–78) was a Queensland government geologist and pioneering field photographer; in 2021 the eastern Kuku Yalanji people won formal ownership of over 160,000 hectares, including the national park.

Which bird of the Amazon rainforest is famous for its huge, brightly coloured bill?

Toucan bills double as radiators: a study of the largest species found the bird can shed body heat by sending extra blood into its bill, much as an elephant does with its ears.

The Mbuti, Efe, Aka and Baka peoples are hunter-gatherers of the rainforests of which region?

Central Africa's forest peoples hunt in different ways: the Efe stalk small game with bows and arrows, while Mbuti bands catch theirs in long nets strung through the Ituri forest.

Which snake, the world's heaviest, hunts in Amazon rivers and swamps?

Green anaconda bites carry no venom: the snake is a boa that waits in the water, seizes prey that comes to drink, coils around it until it suffocates and swallows it whole.

The grooved hair of a sloth's coat hosts what, giving the animal a greenish camouflage?

Symbiotic algae thrive on nitrogen from moths living in the fur, and the sloth eats the algae; when a three-toed sloth climbs down about once a week to defecate, the moths lay their eggs in its dung.

The dazzling colours of poison dart frogs serve mainly to do what?

Warn predators off: the colours advertise toxic skin, yet despite the family's name only a handful of species, all from one genus, were ever used to poison blowgun darts.

Why are golden poison frogs, among Earth's most toxic animals, harmless when bred in captivity?

Their poison comes from wild prey, scientists believe: frogs raised on ordinary feeder insects never develop it, while one wild frog carries enough to kill ten or more people.

The harpy eagle, a giant raptor of the Amazon canopy, feeds mainly on which animals?

Sloths and monkeys make up most of its diet: the eagle snatches them from the branches in its huge talons and is strong enough to fly off carrying a full-grown sloth.

Wild orangutans are native to which two islands?

Borneo and Sumatra are the only places wild orangutans survive, and almost every night each one weaves a fresh sleeping platform high in the trees from bent branches and leaves.

The rainforest-dwelling okapi, striped like a zebra on its legs, is most closely related to which animal?

The giraffe is the okapi's closest living relative, yet the animal stayed unknown to science until 1901, when explorer Harry Johnston sent home strips of its striped hide and, later, a skull.

The capybara, a semi-aquatic grazer of Amazon riverbanks, holds what record?

Largest living rodent and built for water: with partly webbed feet and eyes, ears and nostrils set high on its head, a capybara can hide fully submerged for up to five minutes.

Leafcutter ants carry leaves back to their nests in order to do what?

Farm fungus is exactly what they do: chewed leaves feed an underground garden of fungus that in turn feeds the colony, whose nest can run to more than a thousand chambers and millions of ants.

The Sateré-Mawé people of Brazil use which rainforest insect, sewn into gloves, in initiation rites?

Bullet ants are rated at the very top of the scale for insect-sting pain, and bearing that is the point: an initiate proves himself by pushing his hand into the glove and letting the ants sting him.

Rafflesia arnoldii, a parasite of Southeast Asian rainforest vines, holds which botanical record?

Rafflesia arnoldii bears the largest individual flower, up to about a metre across; it is a parasite with no leaves or stem of its own and smells of rotting meat, hence the nickname corpse flower.

The fluffy, water-repellent seed fibre of the kapok tree was once widely used in what?

Life jackets were stuffed with kapok because the fibre is far lighter than cotton and barely takes up water, staying buoyant even after weeks afloat, until synthetic materials largely replaced it.

Henry Wickham shipped 70,000 seeds of which Amazon tree to Kew in the 1870s, eventually breaking the region's monopoly?

Rubber seedlings raised at Kew were sent on to Britain's Asian colonies, and once those plantations matured their cheaper latex brought the Amazon rubber boom to an end.

Which small nocturnal primate of Southeast Asia's rainforests has enormous eyes and a head that can rotate 180 degrees?

Tarsier eyes are built for hunting in the dark: this is the only primate that eats nothing but animal prey, leaping on insects, lizards and even snakes.

As of 2019, roughly how many mountain gorillas remained in the wild?

About 1,000 is a success story: a 2019 tally reached 1,063, split between the Virunga volcanoes and Uganda's Bwindi forest, and the number has been climbing for years under close protection.

Why is the hoatzin, Guyana's national bird, nicknamed the 'stinkbird'?

It ferments leaves in its gut like a cow, and smells like one too; its chicks hatch with claws on their wings and use them to climb back to the nest after dropping into the water to escape danger.

Which US president's 1913 Amazon expedition and book cemented the piranha's fearsome reputation?

Theodore Roosevelt's Through the Brazilian Wilderness described a piranha feeding frenzy that locals had staged with starved fish; piranhas are in fact omnivores that often eat plant matter.

The Amazon river dolphin is the largest river dolphin and is nicknamed for what?

Its pink colour comes with age: calves are born grey and adult males turn pinkest, while unfused neck vertebrae let the dolphin turn its head to weave between the trunks of the flooded forest.

Roughly what percentage of the sunlight hitting a rainforest canopy reaches the understory?

About 5% of the light hitting the canopy gets through to the understory, and the floor gets only about 2%, which is why it stays relatively clear except near rivers, swamps and clearings.

By some estimates, the rainforest canopy layer is home to what share of all plant species?

By some estimates the canopy holds 50 percent of all plant species; its trees typically stand 30 to 45 metres tall, with epiphytes clinging to their trunks and branches.

Many towering rainforest trees are braced by wide, wall-like flanges flaring from the base of the trunk, called what?

Buttress roots steady giants whose real roots stay shallow, close to the rotting litter that feeds them, by spreading the tree's weight over a wide base.

Bauxite, dug from the deeply weathered red soils of the wet tropics, is the main ore of which metal?

Aluminium is what heavy tropical rain leaves behind: it washes the more soluble minerals out of the soil, sparing the iron oxides that redden it and the aluminium-rich residue mined as bauxite.

Dry rainforests, with their more open canopy, typically occur in what kind of location?

Dry rainforests grow in the rain shadow of mountains, as in parts of eastern Australia; their species often show adaptations such as deciduousness, small leathery leaves, thorns and prickles.

Which trees, found in rainforests worldwide, rely on tiny wasps that breed inside their fruit to pollinate them?

Figs and their wasps cannot breed without each other, and the forest depends on the pair: the fruit is such a vital food for fruit-eating birds, bats and apes that ecologists call fig trees keystone species.

Chicle, a latex tapped from sapodilla trees in Mexico and Central America, was long the main base of which product?

Chewing gum was made from chicle until the 1960s, when most makers switched to a cheaper synthetic base. The Aztecs and Maya had chewed it long before.

The giant water lily of the Amazon, whose floating leaves can reach three metres across, was named for which monarch?

Queen Victoria had only just taken the throne when botanist John Lindley named the lily's genus for her. One leaf grown in Belgium once held a load of 226 kg.

The binturong, a shaggy mammal of Southeast Asian rainforest treetops, gives off a smell often likened to which snack?

Buttered popcorn owes its smell to 2-acetyl-1-pyrroline, the very compound found in binturong urine. The animal's scent clings to bark and warns rivals that the territory is taken.

Vanilla, the second-most expensive spice after saffron, comes from the seed pods of which tropical climbing plants?

Orchids of the genus Vanilla yield just one pod per flower, and growing them takes so much labour that about 95% of vanilla products use artificial flavouring instead.

Which American carmaker built a doomed company town deep in the Amazon rainforest, yet never once visited it?

Henry Ford planned the town, Fordlândia, for 10,000 people, but blight and insects ravaged its close-planted trees. His grandson sold the land at a loss of over $20 million in 1945.

Lemurs, primates found wild nowhere else on Earth, live in the rainforests and dry forests of which island?

Madagascar has about 100 kinds of lemur, and at least 17 larger species have died out since people first settled the island.

The name orangutan is usually traced to two Malay words that together mean what?

Person of the forest is the usual reading, from orang, a person, and hutan, a forest. Malay speakers first used the phrase for forest-dwelling humans, not apes.

A strangler fig, which can end up as a hollow column of roots, begins its life growing where?

In another tree's crown, where a bird has often dropped the seed. The seedling sends roots down to the ground and wraps its host, which can die and rot away inside the fig.

Which flightless rainforest bird, armed with a dagger-like inner claw, is often labelled the world's most dangerous?

Cassowary kicks are fearsome because the inner toe carries a claw up to 125 mm long. The birds live in the humid rainforests of New Guinea, nearby islands and northeastern Australia.

El Yunque, the only tropical rainforest in the US National Forest System, grows in which part of the United States?

Puerto Rico's El Yunque is also the wettest and most biodiverse of the national forests. Spanish foresters surveyed it in 1853, decades before the island passed to the United States.

The Tongass, the largest national forest in the United States and mostly temperate rainforest, lies in which state?

Alaska's Tongass spreads over nearly 17 million acres of the state's southeastern panhandle, and Juneau, the state capital, is the largest community inside it.

Research on the toco toucan showed that its enormous bill, comparable to an elephant's ears, helps the bird do what?

Cool itself down: the bill can adjust its own blood flow and work as a thermal radiator. In a breeze it can radiate several times the heat the resting bird produces.

Which pig-shaped rainforest mammal with a short, flexible snout is most closely related to horses and rhinoceroses?

Tapir snouts can swivel in every direction to grab foliage that would otherwise be out of reach. The Malayan species has the longest of all.

Thor Heyerdahl built his Kon-Tiki raft from logs of which rainforest tree, whose wood is also prized for model aircraft?

Balsa is the softest wood ever measured on the Janka hardness test, yet botanists class it as a hardwood because the tree is a flowering plant, not a conifer.

Which American primatologist spent nearly two decades among Rwanda's mountain gorillas and wrote Gorillas in the Mist?

Dian Fossey worked from the Karisoke Research Center and opposed poaching so head-on that tensions escalated. She was murdered in her cabin there in 1985.

Which houseplant from the tropical forests of southern Mexico is nicknamed the Swiss cheese plant for its holey leaves?

Monstera takes its name from the Latin for monstrous, a nod to those unusual leaves. Young plants have whole leaves, and the holes appear only as they grow.

The most distant source of the Amazon River lies high in the Andes mountains of which country?

Peru holds all three headwaters that have been claimed as the river's source: the Marañón, the Apurímac and the Mantaro, each rising above 5,000 metres.

The Amazon River got its name after Spanish explorers fought women warriors who recalled a tribe from which mythology?

Greek myth told of the Amazons, a tribe of women warriors. The explorers who met fighters led by women on the great river borrowed the name for it.

The Monteverde reserve, named by Quaker settlers from Alabama, protects misty mountain rainforest in which country?

Costa Rica drew the Quakers in 1951 because it had abolished its army three years earlier. The reserve they inspired now shelters over 2,500 plant species and 400 kinds of bird.

Many tall rainforest trees are shallowly rooted, so which flaring, wall-like roots at their base prop them up?

Buttresses can stand as tall as 9 metres. Those of neighbouring trees may knit into a mesh that helps hold up the whole stand.

What name is given to the long woody vines that root in the soil and climb rainforest trees to reach sunlight?

Lianas can form bridges through the treetops, giving sloths and lizards a path from one tree to the next. They stay rooted in the ground all their lives.

Which plant family, which includes the pineapple, often holds pools of water where small rainforest animals live?

Bromeliads with tightly overlapping leaf bases form a tank. One was found to hold a spider, a centipede, a millipede, an ant colony and an earthworm.

Which Amazon river port is the largest mainland city in the world that cannot be reached by road?

Iquitos can be entered only by river or by air. Bull sharks from the Atlantic have been recorded there, thousands of kilometres upstream.

The Great Bear Rainforest, home of the white-furred spirit bear, lines the Pacific coast of which country?

Canada's Great Bear Rainforest covers 6.4 million hectares of British Columbia. Its spirit bears are black bears, and about one cub in ten is born with a white coat.

In the western Amazon, hundreds of macaws gather on exposed riverbanks almost every day to eat what?

Clay with more sodium is what the birds choose, which suggests they come for the salt. An older idea held that the clay soaked up toxins from their diet.

Which lizard of Central American rainforests is nicknamed the Jesus lizard for sprinting across the surface of water?

Basilisk feet have flaps of skin along the toes that catch tiny air bubbles. The flaps fold flat when the lizard walks on land and spread open as it hits the water.

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

Percy Fawcett set out with his eldest son Jack and Jack's friend Raleigh Rimmel, and none of them came back. He had pieced the idea of the city together from old documents by 1914.

Which ancient Maya city, rising from the rainforest of northern Guatemala, doubled as a rebel moon base in Star Wars?

Tikal stood in for the moon Yavin 4 in the 1977 film. Its last inhabitants left around the 10th century, and the rainforest claimed the ruins for the next thousand years.

The Darién Gap, a roadless stretch of rainforest between Panama and Colombia, is the only break in which route?

Pan-American Highway traffic stops at Yaviza in Panama and resumes at Turbo in Colombia, about 106 km away. The rest of the network runs some 30,000 km through the Americas.

Which small apes of Southeast Asian rainforests swing arm over arm at up to 55 km/h and sing duets with their mates?

Gibbons can cover up to 15 metres in a single swing. A mated pair's duet carries about a kilometre, and their young sometimes join in.

Quinine, long the only effective malaria treatment, comes from the bark of which tree of the tropical Andean forests?

Cinchona trees earned the nickname fever trees, and Ecuador, Bolivia and their neighbours held a monopoly on the bark until plantations were set up overseas. Quinine was first synthesised in 1944.

Which naturalist, a veteran of the Amazon and the Malay Archipelago, hit on natural selection independently of Darwin?

Alfred Russel Wallace wrote up the idea in 1858, and his paper was published that year alongside extracts from Darwin's own writings. The Wallace Line between Asian and Australasian wildlife bears his name.

Which rainforest primate of Gabon and Cameroon, with a vivid red and blue face, is the largest monkey in the world?

Mandrill hordes in Gabon's Lopé National Park average about 620 animals, and some reach 845, possibly the largest cohesive groups of any wild primate.

Which snake of Southeast Asian rainforests and woodlands is the longest in the world, at times exceeding six metres?

Reticulated python lengths above 6 metres are rare. One Indonesian snake measured at 6.95 metres had been caught after swallowing a radio-collared sun bear.

Which rainforest bird walls its nesting female inside a tree hollow with mud, droppings and fruit pulp?

Hornbill mothers stay sealed in behind one narrow gap, just big enough for the male to pass food through. The wall can go up in a few hours.

Which country's national bird is a huge forest eagle, once called the monkey-eating eagle, found nowhere else?

The Philippines made the eagle its national bird. The old name came from reports on the island of Samar that it ate only monkeys, but it also takes colugos, snakes and lizards.

Which climbing palms of Southeast Asia's old-growth tropical forests supply the canes used in wicker furniture?

Rattan covers roughly 600 species of climbing palm, and about a fifth of them have commercial value. The stems are light, durable and flexible enough to bend into frames.

Which plant-based arrow poison, long used by hunters in the Amazon, gave surgeons a muscle relaxant in the 1940s?

Curare paralyses only when it enters the bloodstream, so hunters could safely eat what they shot. Doctors in Montreal brought it into the operating theatre as an aid to anaesthesia in 1942.

The electric eel of Amazon rivers, which can deliver 860-volt shocks, is not a true eel but a type of what?

Knifefish relatives of the electric eel are mostly only weakly electric: they sense their surroundings with the field but cannot deliver a shock.

Which giant Amazon fish, up to three metres long, must keep coming to the surface to gulp air?

Arapaima have a swim bladder of lung-like tissue that lets them breathe at the surface. The habit makes them easy prey for fishermen, who wait with harpoons.

What Portuguese name is given to the fertile soil ancient Amazonians made with charcoal, bones and pottery?

Terra preta means black soil. Its charcoal stays in the ground for thousands of years, binding the minerals that crops need, and farming communities were making it by 450 BCE.

The pororoca, which surfers ride far up the Amazon River from the sea, is what kind of natural phenomenon?

A tidal bore forms when the incoming tide reverses the Amazon's flow, and this one sends waves up to 4 metres high as far as 800 km inland. Its name may come from a Tupi word for a great roar.

What name is given to the streams of water vapour that Amazon trees release and winds carry across the continent?

Flying rivers begin with transpiration: one large tree can release 1,000 litres of water vapour a day. The Andes then turn the moist air aside, and it falls as rain as far away as Paraguay and Uruguay.

Which Indigenous people, about 35,000 strong, live in rainforest villages along Venezuela's southern border?

Yanomami villages are politically independent, and their people do not see themselves as one united group. A biosphere reserve was created in 1993 to protect their territory and way of life.

Henry Walter Bates, who explored the Amazon rainforest from 1848, gave the first scientific account of what in animals?

Mimicry in which a harmless species copies the warning signals of a harmful one is called Batesian in his honour. He wrote up his travels in The Naturalist on the River Amazons.

The Valdivian temperate rainforest fills a narrow coastal strip between the Pacific and the Andes in which country?

Chile's Valdivian forests give way to Mediterranean scrub in the north, and much of the region lay under the Patagonian Ice Sheet at the peak of the last ice age.

Cacao is one of many rainforest trees with cauliflory, meaning their flowers and fruit grow where?

Directly on the trunk and main stems, a habit thought to help bats and other climbing animals reach the nectar and fruit.

The dazzling blue of the morpho butterflies of the Amazon's forests comes not from pigment but from what?

Layered wing scales reflect light again and again, and the interference leaves a brilliant blue. Engineers have copied the trick for dye-free paints and anti-counterfeit marks on currency.

Which tarantula of the Amazon rainforest, the heaviest spider in the world, lives in deep burrows in swampy places?

Goliath birdeater spiders weigh up to 175 grams, yet despite the name they rarely catch birds. Most of their diet is large arthropods, worms and amphibians.

Which reddish-brown timber from tropical American trees became a favourite of British furniture makers in the 1700s?

Mahogany deepens in colour with age, and the great girth of mature trees gave cabinetmakers unusually wide boards to work with.