148 Fun Facts About Nature

Which is the largest ocean on Earth by surface area and volume?

The Pacific is bigger than all of Earth's land combined; Magellan named it the 'peaceful sea' in 1520 because its waters seemed so calm.

What is the biological process by which plants convert light energy into chemical energy?

Photosynthesis in ancient cyanobacteria is what filled Earth's air with the oxygen we breathe, in what geologists call the Great Oxidation Event.

Which lizard family has eyes that swivel independently and a tongue up to twice its body length?

A chameleon changes colour mostly to signal mood, rivals and mates, or to handle temperature, not mainly to hide.

What is the most abundant gas in Earth's atmosphere?

Nitrogen makes up about 78% of air, yet the gas does almost nothing for living things until the nitrogen cycle fixes it into compounds they can use.

Which desert is considered the largest hot desert in the world?

The Sahara Desert is far more than sand dunes: much of it is rocky plateau and gravel plain, because the wind carries loose sand away.

What is the highest mountain in Africa?

Mount Kilimanjaro sits just south of the equator, yet its summit holds glaciers, which lost about 85% of their ice between 1912 and 2011.

Which spot in the Mariana Trench is the lowest known point on the seabed?

Challenger Deep is named after HMS Challenger, whose crew first sounded the trench's depths in 1875 during a round-the-world science voyage.

What is the largest living reptile?

The saltwater crocodile, the largest living reptile, is a strong ocean traveller, turning up far out at sea and on remote islands.

What is the scientific study of fungi called?

Mycology studies organisms that look and grow like plants, yet fungi are genetically closer to animals than to plants.

Aspirin's natural forerunner, salicin, comes from the bark of which tree?

Willow bark has eased pain and fever since antiquity, yet Bayer named Aspirin after meadowsweet, Spiraea, another plant that yields the same acid.

What is the largest living species of fish?

The whale shark is the biggest fish in the sea, yet it filter-feeds on tiny prey and is docile enough to pose no real threat to people.

Which gas do plants take in from the air to make their food?

Carbon dioxide and water go in and oxygen comes out, but that oxygen comes from splitting the water, not the carbon dioxide.

California's San Andreas Fault, where two plates slide past each other, is which type of plate boundary?

Transform boundaries neither make nor destroy crust, and a 1906 rupture of the San Andreas set off the fires that devastated San Francisco.

Which biome has permafrost and low-growing vegetation like mosses and lichens?

Tundra soil has long stored carbon in its permafrost, yet in 2024 NOAA reported that, counting wildfires, the Arctic tundra now gives off more carbon than it absorbs.

Which type of cloud is typically thin, wispy, and found at high altitudes?

Cirrus clouds are wispy streaks of ice crystals, and they are often the first sign of an approaching warm front, with rain on the way.

In which layer of Earth's atmosphere is most of the ozone layer found?

The stratosphere gets warmer the higher you go, because ozone there absorbs the Sun's ultraviolet light and heats the air.

Which leaf structures release most of the water a plant loses through transpiration?

Stomata let water out whenever they open to take in air, so cacti and many other desert plants open theirs mainly at night, when less water is lost.

To which phylum do starfish and sea urchins belong?

Echinodermata include starfish, which feed by pushing their stomach out through their mouth to digest a clam inside its own shell.

Which mineral sits at 1, the very bottom of the Mohs hardness scale, soft enough to scratch with a fingernail?

Talc's sheets of atoms are held together only by weak bonds, so they slip past one another, which makes talc soft enough to crumble into talcum powder.

What mainly causes Earth's seasons?

Axial tilt drives Earth's seasons, which is why they are reversed between hemispheres: when the north tilts toward the Sun, the south has winter.

Which rock type forms when molten magma or lava cools and solidifies, as granite and basalt do?

Igneous rock that cools slowly underground grows large crystals, as in granite, while lava that cools fast at the surface stays fine-grained, like basalt.

Which kind of relationship between two species leaves both better off?

Mutualism benefits both partners: clownfish shelter unharmed among a sea anemone's stinging tentacles, and in return drive off fish that would eat the anemone.

What is the scientific study of plants called?

Botany grew up alongside medicine: Padua's university garden, founded in 1545 and still in place, was planted so students could tell real medicinal herbs from fakes.

Which burrowing Australian marsupial is famous for its cube-shaped droppings?

Wombat droppings get their corners from stiffer and softer bands in the gut wall, and the flat sides may help them stay put where wombats leave them to mark territory.

What term describes organisms such as plants that make their own food from inorganic sources?

Autotrophs don't all need sunlight: microbes at deep-sea vents make food from chemicals such as hydrogen sulfide, feeding tubeworms and shrimp in the dark.

Which Australian animal can mimic chainsaws and car engines?

The Lyrebird mixes its own song with copied sounds, and males sing this medley while dancing on a mound with their tails thrown forward over their heads.

Which Siberian lake is the deepest lake on Earth?

Lake Baikal is so deep because it lies in a rift valley where Earth's crust is slowly pulling apart.

What is the hardest known natural mineral?

Diamond is the hardest natural material, so industry uses diamonds as abrasives to cut and polish other stones, and even other diamonds.

Which layer of Earth's atmosphere is closest to the surface and where most weather occurs?

The troposphere's rising, churning air makes weather and turbulence, which is why airliners often cruise just above it, where the air is calmer.

Which carnivorous plant is native only to the wetlands of North and South Carolina?

The Venus flytrap has long been poached from the wild for the plant trade, and in 2014 North Carolina made that poaching a felony.

What is the largest land animal by mass?

The African bush elephant keeps cool by flapping its huge ears, which fan air over large blood vessels and radiate away body heat.

Which scale was devised to measure the magnitude of earthquakes?

The Richter Scale has been replaced by seismologists with the moment magnitude scale, which gives more reliable sizes for large quakes.

What may follow when the sea suddenly retreats from shore?

A Tsunami can pull the sea back and bare the seabed before it rushes ashore, and people who read that sign and head for high ground can escape.

Which animal gives birth to its young in mid-winter while dormant in its den?

A mother Bear nurses her cubs in the den until spring without eating, living on body fat she built up by feeding heavily all summer and fall.

Which tree species includes Methuselah, credited as the oldest known living non-clonal tree?

Bristlecone Pine trees can outlast millennia by strip-bark growth: in very old trees, only a narrow strip of living bark keeps a few branches alive.

Which rock type forms when layers of sand, mud and shell fragments are buried and cemented together, often trapping fossils?

Sedimentary rock includes coal, because coal forms when layers of plant remains are buried and compressed over millions of years.

What is the process called when water changes from a liquid to a gas?

Evaporation carries heat away from the water left behind, which is why power plants cool hot water by letting some of it evaporate in cooling towers.

Which bird lays its eggs in other birds' nests and leaves them to raise its chicks?

A female Cuckoo removes one of the host's eggs and lays her own in its place, often a close match for the host's eggs, so the swap is hard to spot.

Which Cuban bird, weighing about two grams, is the smallest living bird on Earth?

A female Bee hummingbird builds the tiny cup-shaped nest and raises the chicks all by herself.

Which major South American river has no bridge spanning it anywhere?

The Amazon River has no bridge, not because it is too wide but because it flows mostly through rainforest with few roads, so people cross by ferry.

Which are the only mammals capable of sustained, powered flight?

Bats are the only mammals capable of sustained flight, and vampire bats find blood vessels in their prey using heat sensors around the nose.

Which living animal is the largest known to have ever existed?

The Blue whale, the largest animal known to have existed, lives almost entirely on krill, which it strains from seawater through its baleen plates.

What term describes the variety of life found on Earth or in one particular region?

Biodiversity is richest in the tropics, where a warm climate and high plant productivity support far more species than the polar regions.

What sits at the base of most marine food webs as the primary producer?

Phytoplankton are too small to see with the naked eye, yet they produce about half of the oxygen on Earth.

Which wild cat has black 'tear marks' down its face?

The Cheetah is the fastest land animal, yet it can't roar like a lion; it purrs, hisses and chirps instead.

What instrument is used to measure wind speed?

An Anemometer is normally set on a 10-metre mast, because buildings, trees and rough ground slow and disturb the wind near the surface.

Which type of forest is defined by broadleaf trees that drop their leaves every autumn, blazing with colour first?

Autumn colour is mostly unmasking: as chlorophyll breaks down, the carotene and xanthophyll pigments already in the leaf show through. Deciduous forests are dominated by broadleaf trees that shed every fall.

Which country is home to the volcanoes Krakatoa and Tambora?

Indonesia's Tambora blew up in 1815, and its debris chilled much of the planet, so crops failed across the Northern Hemisphere the following year.

What is the process by which water vapor in the air changes into liquid water, forming clouds?

Condensation releases heat into the surrounding air, and that released heat is what feeds a hurricane's powerful winds.

Which monitor lizard, the world's largest lizard, lives wild only on a handful of islands including Flores and Rinca?

A Komodo dragon's bite delivers venom that stops blood clotting and sends prey into shock, even if the animal escapes the attack.

Which seabird migrates farther than any other, travelling from the far north all the way to Antarctica?

The Arctic tern flies from the Arctic to the Antarctic and back each year, so it gets to see two summers every year.

What happens to an Alaskan wood frog's heart during the months it spends frozen?

It stops beating entirely, and breathing stops too; a natural antifreeze keeps ice out of the frog's cells, so it can thaw and revive in spring.

Socialist settlers once named the giant tree now called General Sherman after which thinker?

Karl Marx was the tree's name until Congress made the colony's land a national park in 1890; the colony collapsed and the name General Sherman returned.

Hyperion, the tallest known living tree on Earth, belongs to which species?

Coast redwood Hyperion drew so many visitors that trampling wiped out the ferns around it, and since 2022 its area has been closed, with fines or jail for entering.

Pando, a single organism of over 40,000 trunks in Utah's Fishlake National Forest, is a clone of which tree?

Quaking aspen Pando is shrinking because deer and elk browse its young shoots, so few new trunks replace the dying old ones.

How many true leaves does the Namib Desert plant Welwitschia grow in its whole lifetime?

Two leaves, the seedling's originals, keep growing for Welwitschia's whole life of centuries, which is why its Afrikaans name means 'two leaves, can't die'.

Which country's Lake Maracaibo has the highest density of lightning on Earth?

Venezuela's Lake Maracaibo gets almost 250 lightning flashes per square kilometre a year, as warm, moist air off the lake is forced up against the Andes.

Thin sheets of wind-driven ice move the 'sailing stones' across a dry lakebed in which US national park?

Death Valley's Racetrack Playa briefly floods in winter, and when its thin ice breaks up under light winds it shoves the rocks along, as GPS-tagged stones showed in 2013-14.

Which desert is the driest non-polar desert in the world?

The Atacama is so dry, with almost no microbial life in places, that scientists test Mars mission instruments there.

Which coral reef system is the largest structure built by living organisms?

The Great Barrier Reef is built by billions of tiny coral animals, yet together they have made the largest living structure on Earth.

A mantis shrimp's club strikes so fast that it generates what in the water around it?

Vapour-filled bubbles form because the club moves so fast, and when they collapse they land a second blow, so each strike hits the prey twice.

Which sea creature has three hearts?

An Octopus's main heart stops beating while it swims, which helps explain why it mostly crawls instead.

Which tiny animals, nicknamed water bears, have survived exposure to outer space?

Tardigrades can dry out into a curled-up 'tun' state, and in that form they shrug off vacuum and ionizing radiation.

Which sea creature is nicknamed 'immortal' because it can turn back into a young polyp after maturing?

One Jellyfish, Turritopsis dohrnii, makes that switch after injury or harsh conditions such as a sudden temperature change, so a crisis restarts its life.

A honey bee's waggle dance, which tells hivemates where food is, traces which shape?

A figure eight is the shape, and the waggle run through its middle points the way: its angle from vertical matches the food's angle from the Sun.

Which insect defends itself by firing a near-boiling chemical spray from its rear?

The Bombardier beetle mixes hydroquinone and hydrogen peroxide in its abdomen, and the reaction's heat brings the spray near boiling and blasts it out.

Which emperor penguin parent incubates the pair's single egg while the other heads to sea to feed?

The male balances the egg on his feet for just over two months of Antarctic winter, eating nothing while the female feeds at sea.

Which plant produces the largest single bloom in the world?

Rafflesia arnoldii has no leaves, stems or roots: it lives as a parasite inside jungle vines, and its giant flower is the only part that shows.

Why do so-called corpse flowers reek of rotting meat?

Corpse flowers reek to attract insect pollinators such as carrion beetles and flesh flies, and some even warm their flower spikes to spread the smell.

Auroras form when charged particles funnelled down Earth's magnetic field hit which gases?

Excited oxygen and nitrogen release their extra energy as light when they settle back down — much the way a neon lamp works.

What does the Enhanced Fujita Scale use to rate a tornado's intensity?

The damage it causes is surveyed after a tornado passes, and experts work backwards from it to estimate the tornado's wind speeds.

Which mammal protects kelp forests by eating the sea urchins that graze them?

Sea otters often crack open shellfish by smashing them against a rock balanced on their chests.

Where do eastern monarch butterflies fly, some as far as 3,000 miles, to spend the winter?

Mexico's oyamel fir forests host the eastern monarchs each winter, and it takes several generations of butterflies to complete the trip back north.

How long ago did the asteroid impact that ended the Cretaceous period occur?

66 million years ago the Chicxulub asteroid struck, wiping out the non-avian dinosaurs and leaving a crater now buried under the Yucatán Peninsula.

Which moon of Saturn is the only world besides Earth known to have lakes on its surface?

Titan's lakes hold liquid methane and ethane, and like Earth it has clouds, rain and rivers, only of hydrocarbons instead of water.

Where is most of Earth's fresh water?

Ice sheets and glaciers hold most of Earth's fresh water, and if Antarctica's ice sheet melted, global sea level would rise by almost 60 metres.

Which Arctic whale's spiralled 'unicorn horn' is really an overgrown tooth?

A Narwhal's tusk is a tooth grown into a long spiral, and scientists think it may help attract mates or sense changes in the water.

Which Ice Age giant still roamed an Arctic island when Egypt's pyramids were built?

Woolly mammoths on Wrangel Island were cut off from the mainland about 10,000 years ago, so they outlived mainland mammoths by about 6,000 years.

Which bird of prey, diving in a 'stoop' at over 320 km/h, is often called the fastest animal on Earth?

Suzuki named its Hayabusa superbike after this bird, using the Japanese word for peregrine falcon. In its hunting dive, the stoop, it can top 320 km/h, making it arguably the fastest animal alive.

Which animal has the largest brain on Earth, over five times heavier than a human's?

The Sperm whale's head holds spermaceti, a waxy oil so prized that sperm whales became a prime target of the whaling industry.

Which fish holds the record for the longest lifespan of any known vertebrate?

Greenland sharks grow so slowly that they reach maturity only at around 150 years old, and one was estimated at 392 years, give or take 120.

The shores of which body of water are the lowest land-based elevation on Earth?

The Dead Sea is almost ten times saltier than the ocean, so its water is dense enough that swimming in it feels like floating.

Which Arctic species may be the longest-lived mammal, reaching more than 200 years?

Bowhead whales can live more than 200 years, and old stone harpoon tips found in hunted whales first hinted at their extreme ages.

The aye-aye, a primate that taps tree trunks with a thin middle finger, is native to which island?

The aye-aye lives only on Madagascar, where it taps trees, listens for hollows where grubs hide, then gnaws in and hooks them out with that finger.

Where does a male platypus carry the spur that delivers its painful venom?

On each hind foot a male platypus carries a spur that delivers extremely painful venom; females are born with the spurs too, but lose them.

Why is a horseshoe crab's blood bright blue?

It carries copper, not iron: its oxygen-carrying hemocyanin turns the blood blue, and that blood is so valuable to medicine that the crabs are harvested for it.

Based on median lethal dose in mice, which snake is regarded as the world's most venomous?

The Inland taipan's venom is the most toxic of any snake tested on mice, yet it is shy and placid and rarely meets people in its remote habitat.

Which flightless bird is the largest living species of bird?

The common ostrich is the world's largest bird, and although it cannot fly, a kick from its powerful legs can kill a lion.

Coral 'bleaches' white when stressed polyps expel what?

Symbiotic algae called zooxanthellae live in coral tissue and give it colour, so a bleached coral has lost them, though it is not dead yet.

Roughly how hot does the air around a lightning flash get?

About 30,000 °C, around five times hotter than the Sun's surface, and air heated that suddenly expands with a shock wave we hear as thunder.

Which shorebird flies Alaska to New Zealand, the longest non-stop flight of any bird?

Bar-tailed godwits fly nonstop for about eight days, fuelled by the biggest fat loads of any migratory bird studied, after shrinking their digestive organs.

How many neck vertebrae does a giraffe have?

Seven, like most mammals: a giraffe's neck gets its length from each of those vertebrae being hugely elongated, not from extra bones.

Which living bird has the greatest known wingspan?

The Wandering albatross uses its record wingspan to ride ocean winds, gliding for hours without even a flap of its wings.

The saguaro cactus, which may take 75 to 100 years to grow an arm, is native to which desert?

The Sonoran Desert saguaro soaks up rainwater and its pleats expand like an accordion to hold it, then contract as it uses the water in dry spells.

Which is the world's largest freshwater body by surface area?

Superior, at about 82,000 km², has the largest surface of any freshwater lake, yet the far deeper Lake Tanganyika holds more water.

Where do wild poison dart frogs get the toxins in their skin?

From the prey they eat: poison dart frogs raised in captivity on crickets and fruit flies don't become toxic.

Despite its name, the electric eel is actually a type of what?

Knifefish is the group: electric eels are not true eels, and these air-breathers can even leap from the water to shock a threat.

Which bird of prey can turn its head as much as 270 degrees?

An Owl can't move its large eyes in their sockets, so it turns its head instead, and its forward-facing eyes give it depth perception for hunting in dim light.

Which Australian animal has fingerprints so human-like that a microscope struggles to tell them apart?

The koala is no close cousin of ours: fingerprints evolved separately in climbers that need a sure grip, and its prints can fool even an electron microscope.

Which wading bird hatches greyish and gets its adult colour only from pigments in the food it eats?

The flamingo gets its colour from carotenoids in the plankton it eats, which enzymes in its liver break down into pink and red pigments.

Which rainforest mammal climbs down from the treetops only about once a week, to relieve itself?

The sloth carries a small ecosystem in its shaggy coat, including moths found nowhere else, and buries its weekly droppings in a hole it digs.

What actually fills a camel's hump, despite the common myth that it is a water tank?

Fatty tissue in the hump is a calorie reserve, not a canteen: a thirsty camel can gulp well over 100 litres of water at one go, but none of it is stored there.

Which tiny animal kills more people each year than any other, through the diseases it carries?

The mosquito that bites is always a female: both sexes sip nectar, but in many species she needs the protein in blood to produce her eggs.

In which fish does the father carry the eggs in a belly pouch and then give birth to the young?

The seahorse female places up to 1,500 eggs in her mate's brood pouch, and he typically gives birth at night, ready for another batch by morning.

Which Australian animal, the largest living marsupial, can cover eight or nine metres in a single leap?

The red kangaroo starts out tiny: its newborn is blind, hairless and only a few centimetres long, yet big adults stand more than 1.8 metres tall.

Which flightless bird of Mauritius vanished within a century of Dutch sailors first recording it?

The dodo was really a giant flightless pigeon, and the last widely accepted sighting came in 1662, only 64 years after that first Dutch report.

Bamboo, which can grow almost a metre in a single day, belongs to which plant family?

Grasses count bamboo as their giant: the largest species sends up stalks 46 metres long, each weighing as much as 450 kilograms.

What makes the sound of thunder that rumbles in the seconds after a lightning flash?

Rapidly expanding air along the bolt's path makes a sonic shock wave, and counting the seconds to the rumble, about three per kilometre, tells how far off the strike was.

Which flightless New Zealand bird is the only bird with nostrils at the very tip of its beak?

The kiwi is about the size of a chicken yet lays an egg roughly six times as big as a hen's, one of the largest for its body size of any bird.

Which is the largest cat native to the Americas, with a bite that can pierce a turtle's shell?

The jaguar is outsized worldwide only by the tiger and the lion, and it often kills by biting straight through the skull of its prey.

Which group of animals usually starts life in water as a gilled larva, then grows lungs to breathe air?

Amphibians also breathe through their skin, and some small salamanders and frogs have no lungs at all and rely on it entirely.

Which icicle-shaped cave formations hang from the ceiling, built up by dripping mineral-rich water?

Stalactites often begin as hollow 'soda straws' only a few millimetres wide, while the drops that fall from their tips build a mound on the floor below.

Which hefty African animal has whales, not pigs, as its closest living relatives?

The hippopotamus and the whales share a semiaquatic ancestor: their two lineages split from each other only about 55 million years ago.

Which is the only kind of deer in which the females, too, can grow antlers?

Reindeer of both sexes regrow their antlers every year under a furry skin called velvet, which is shed or rubbed off once the bone beneath has hardened.

Which ape, together with its sister species the bonobo, is the closest living relative of humans?

The chimpanzee is a toolmaker too: nearly every wild population has been seen shaping sticks, rocks and leaves to get at honey, termites and nuts.

Which gem forms inside a living shellfish, built up in layers around a trapped irritant?

A pearl is made of the same calcium carbonate as its host's shell, and almost any shelled mollusc can produce one, though very few are gem quality.

Which islands are home to the finches collected on the Beagle voyage and now named after Charles Darwin?

The Galápagos finches number about 18 species, and all but one of them live nowhere else on the planet.

Which waterfall, the world's tallest uninterrupted drop, is named after an American pilot who flew over it?

Angel Falls took the name after Jimmie Angel wrecked his plane trying to land on the plateau above and spent 11 days walking back to civilisation.

By what name is a hurricane known when it forms off East Asia, near Japan and the Philippines?

Typhoon country is the busiest storm basin of all: it spawns almost one third of the world's tropical cyclones, and they can form there in any month.

Which pigment, which soaks up mainly red and blue light, gives the leaves of most plants their green colour?

Chlorophyll masks other colours all summer: when it breaks down in autumn, the yellows and oranges that were in the leaf the whole time finally show.

A snowflake's arms sprout from the corners of which shape, the form its ice crystal first takes?

A hexagon is where every snowflake starts, yet fewer than one in a thousand grows into the perfectly symmetrical six-armed star of the picture books.

Which antelope makes up the bulk of the herds in the Serengeti's annual Great Migration?

Wildebeest travel the loop alongside zebras and gazelles, and each February the cows give birth to hundreds of thousands of calves within two or three weeks.

What name is given to the two days each year when day and night are almost exactly the same length?

Equinox comes from the Latin for 'equal night', although the match is never exact: sunlight bent by the atmosphere stretches the daytime a little.

A moth spins a silk cocoon, but what name is given to the pupa of a butterfly?

A chrysalis is not a bag of caterpillar soup, whatever the popular belief: the larva never completely liquefies while it rebuilds itself as an adult.

Amber, the golden gem that sometimes holds ancient insects whole, is the fossilised form of what?

Tree resin starts out soft and sticky, which is how insects ended up sealed inside; the oldest amber known formed about 385 million years ago.

Which volcanic rock is so full of gas bubbles that it can float on water for years?

Pumice is frothy volcanic glass that can be 85 per cent empty space, so it stays afloat until it finally becomes waterlogged and sinks.

Which material is a rhinoceros's horn made of?

Keratin makes the horn grow much as a fingernail does, and there is no good evidence that swallowing it brings any health benefit.

What is the natural glow of fireflies and deep-sea anglerfish called?

Bioluminescence is the norm in the dark ocean: in one survey of open water, about three quarters of the main groups of deep-sea animals could make light.

With which body part does a butterfly taste a leaf before laying eggs on it?

Its feet carry taste sensors that work only on contact, so a female can check that her caterpillars will be able to eat the leaf she has chosen.

Which massive-trunked African tree is nicknamed the 'upside-down tree' for its strange silhouette?

Baobab trunks cannot be dated by counting rings, because the tree does not always lay one down each year, and they swell and shrink with the rains.

What name describes a long, steep-sided sea inlet gouged out by moving ice?

A fjord is often deeper than the sea outside it: Norway's Sognefjord plunges as much as 1,300 metres below sea level.

Which spiny Australian anteater is the only mammal besides the platypus that lays eggs?

The echidna lays a single leathery egg straight into her pouch, and hunts ants and termites with electrosensors in her long snout.

What word describes animals such as bushbabies and tarsiers that are active at night and sleep by day?

Nocturnal animals often have very large eyes for their body size, which gather more of what little light the night has to offer.

Sunlight bent and reflected inside raindrops makes a rainbow whose main bow has which colour on its inner edge?

Violet lines the inside of the main bow, but in the fainter second arc of a double rainbow the colours appear in reverse order.

Which seasonal reversing wind brings heavy summer rains to India from the Arabian Sea and Bay of Bengal?

Monsoon usually means the rainy phase, but strictly the term covers the dry season too, when the wind swings round and blows the other way.

What gives a beaver's ever-growing front teeth their orange colour?

Iron in the enamel colours a beaver's incisors orange or reddish-brown, and they keep growing all its life as it gnaws through the trees it fells for dams and lodges.

Which birds have a tongue bone so long that it winds around the outside of the skull?

Woodpeckers need the length: the bone supports a long, sticky tongue that reaches deep into the holes they drill to extract insects and larvae.

Which US state has Mauna Kea, a volcano taller than Everest if measured from its base on the sea floor?

Hawaii's dormant giant rises more than 9,000 metres from the ocean floor, and thirteen telescopes funded by eleven countries have been built on its dry summit since the 1960s.

Which 'living fossil' fish, once known only from ancient rocks, was caught alive off South Africa in 1938?

The coelacanth belongs to a group whose fossils go back more than 400 million years; a second living species turned up in Asian waters in the late 1990s.

Which sea, named after its floating brown seaweed, is the only one with no land boundaries?

The Sargasso Sea is hemmed in by four ocean currents instead of land, and expeditions in the 1920s showed that European eels cross the Atlantic to breed there.

Which palm, native to the Seychelles, produces the largest seed in the plant kingdom?

Coco de mer fruit can weigh 45 kilograms, and its seed was once wrongly believed to be a sea-bean, evolved to be scattered by ocean currents.

Which lizard-like New Zealand reptile is the sole survivor of an order from the age of dinosaurs?

The tuatara looks like a lizard but is not one: its order peaked in the Jurassic as the world's dominant small reptiles, then dwindled to a single species.

Which striped-legged forest animal of the Congo is the only living relative of the giraffe?

The okapi wears zebra-like stripes yet belongs to the giraffe family, and science formally recognised it as a species only in 1901.

Which deep-sea animal has the largest eyes documented in the animal kingdom, each up to 30 cm across?

The colossal squid's eyes even carry their own headlights: light-producing organs beside each lens make them glow in the dark.

Which tree, the last living species of its ancient order, has specimens that survived the Hiroshima bomb?

Ginkgo biloba was thought extinct in the wild for centuries and lived on through cultivation; gardeners also know it as the maidenhair tree.

Which country is home to Son Doong, the world's largest known cave passage, with its own river?

Vietnam's giant went unsurveyed until 2009, when a caving expedition measured its volume at about 38.5 million cubic metres.

Which complex mirage warps distant ships and coastlines seen in a narrow band just above the horizon?

Fata Morgana is Italian for Morgan le Fay, and the mirage can warp a distant ship or shore until it is completely unrecognisable.

What Arabic-derived name is given to the towering wall of dust pushed ahead of a collapsing thunderstorm?

A haboob over Khartoum has been recorded up to 2,000 metres high and moving at 70 km/h; the word was first used for the dust storms of Sudan.