49 Fun Facts About Dinosaur Extinction

Roughly how many years ago did the extinction that wiped out the non-avian dinosaurs occur?

66 million years replaced the long-quoted 65 million after sharper argon dating, which in 2013 also showed that the impact and the extinction fell within about 32,000 years of each other.

Which famous dinosaur was still alive when the asteroid struck at the end of the Cretaceous?

Triceratops was one of the very last non-avian dinosaurs, whereas Stegosaurus, Diplodocus and Allosaurus were already ancient fossils, having died out about 80 million years before the impact.

By what earlier name was the K-Pg mass extinction commonly known?

The K-T (Cretaceous-Tertiary) label gave way after geologists retired 'Tertiary' as a formal period and split its span between the Paleogene and the Neogene, so the boundary took the Paleogene's 'Pg'.

Which metal, more common in asteroids than in Earth's crust, is unusually abundant in the K-Pg clay?

Iridium is scarce in Earth's crust because most of it sank into the core with iron, so a worldwide spike of it in one thin clay layer pointed to something arriving from space.

Which father-and-son team proposed in 1980 that an asteroid impact killed the dinosaurs?

Luis and Walter Alvarez had no crater to point to, and the idea met years of scepticism; Luis, a Nobel-winning physicist, died in 1988, shortly before the matching scar was finally identified.

The clay layer that inspired the asteroid theory of dinosaur extinction was first sampled in which country?

Italy's Gubbio gorge gave the first samples, and when the same rare-metal spike turned up in Denmark and New Zealand the team knew the fallout had settled worldwide.

The asteroid blamed for wiping out the dinosaurs was closest in size to which of these?

Mount Everest is the usual yardstick: at roughly 10 km across the rock would have stood taller than the mountain, yet it struck hard enough to gouge a crater well over a hundred kilometres wide.

On which peninsula does the Chicxulub crater lie?

The Yucatán, Mexico, shows no crater at the surface: the scar lies buried under about a kilometre of younger rock, which is why it stayed hidden until geophysical surveys picked it out.

Which body of water covers half of the buried Chicxulub crater?

The Gulf of Mexico covers the crater's northern half, and in 2016 a drilling rig offshore cored into its peak ring, a circle of hills thrown up within minutes of the impact.

The Chicxulub crater was first noticed in the late 1970s by geophysicists looking for what?

Petroleum surveys for Pemex mapped the buried ring, but the company judged it an old volcano; only when stored drill cores were re-examined around 1990 did shocked rock prove it was an impact scar.

What surface features, visible in satellite images, trace an arc above the buried rim of the Chicxulub crater?

Cenotes (sinkholes) ring the buried rim, probably because groundwater heading for the coast is steered along it and eats the limestone above into flooded pits.

Grains of which common mineral, scarred by shock waves, turn up in the K-Pg boundary clay and helped prove an impact?

Quartz takes on those microscopic scars only under a sudden, immense pulse of pressure, of the kind otherwise known from nuclear blasts and meteorite craters.

What covered the spot where the dinosaur-killing asteroid came down?

A shallow tropical sea covered the site, so the ocean poured straight back into the fresh crater: drill cores show about 130 m of debris settled there on the very first day.

The dinosaur-killing asteroid struck rock rich in which element, making its aftermath deadlier?

Sulfur vapour from the target rock is counted among the main drivers of the die-off, but a 2025 study of the crater and its fallout found about five times less of it than models had assumed.

How did the Chicxulub impact chiefly cause the mass extinction?

A long winter that halted photosynthesis followed as dust and soot dimmed the sun for many months, so plants and plankton died first and the animals above them starved up the food chain.

Tiny spherules found in the boundary clay formed from what?

Droplets of molten rock from the impact froze into glass beads in flight and rained down far away; some ended up lodged in the gills of fish that were buried within hours.

Which vast volcanic province is the leading rival, or contributing, explanation for the dinosaurs' extinction?

The Deccan Traps of India were erupting when the asteroid hit, but a 2020 modelling study found that only the impact made the world unlivable for dinosaurs, while the eruptions may even have softened the blow.

Lava provinces like those blamed in some dinosaur-extinction theories are called 'traps' after a Swedish word for what?

Stairs, 'trappa' in Swedish, fit because flat sheets of old lava weather back into giant steps, giving such hills the look of a staircase.

Which earlier mass extinction, nicknamed the Great Dying, was even deadlier than the one that killed the dinosaurs?

The end-Permian extinction, the worst on record, cleared the way for the dinosaurs themselves: their ancestors rose in the emptied world it left behind.

Which geological epoch opened immediately after the extinction of the non-avian dinosaurs?

The Paleocene opened on an emptied world, and fossil leaves and pollen from Colombia show its forests closed over into dense, shaded canopies like today's rainforests.

Why are crocodilians thought to have outlasted the non-avian dinosaurs?

They can go months without food, and big adults far longer, because cold-blooded bodies burn so little fuel, which let them wait out the long collapse of the food chain.

Which group of dinosaurs survived the extinction and radiated into today's species?

Birds came through, but only just: one leading study suggests forests collapsed worldwide, wiping out the tree-dwelling kinds, so that today's species descend from ground-living survivors.

Which winged animals, often mistaken for dinosaurs, died out entirely in the K-Pg extinction?

Pterosaurs are often called flying dinosaurs but were a separate branch of reptiles, and unlike the dinosaurs they left no living descendants at all.

Which giant sea reptiles, like the one that steals scenes in Jurassic World, died out in the K-Pg extinction?

Mosasaurs were not dinosaurs but giant seagoing lizards, in the same group as today's lizards and snakes, and they were still thriving worldwide when the asteroid struck.

Which shelled sea animals, lookalikes of the living nautilus, died out at the K-Pg boundary?

Ammonites look like nautiluses but were probably closer kin to squid and octopuses; deep-living nautiluses are thought to have escaped the worst of the surface-water collapse.

The K in K-Pg comes from 'Kreide', the German word for which rock that also names the Cretaceous?

Chalk gives the Cretaceous its name, from 'creta' in Latin, because the period's seas laid down thick white beds like those of southern England.

Which sea animals, which house algae in their tissues, were among the worst-hit groups in the K-Pg extinction?

Corals that built sunlit reefs lost most of their kinds because their live-in algae need light, while solitary deep-water forms, which have no such partners, came through far better.

Which kinds of land animals came through the K-Pg extinction best?

Omnivores, insectivores and scavengers could live off the dead: insects, worms and snails feed on rotting matter, the one food supply that kept going when green plants failed.

What size were the mammals that survived the extinction, generally?

About rat-sized survivors did not stay small for long: within roughly 700,000 years some mammals weighed 50 kg, a hundred times as much as the animals that had come through the impact.

Which giant meat-eater was among the very last dinosaurs, living right up to the asteroid impact?

Tyrannosaurus rex appeared only in the dinosaurs' final two or three million years, whereas Spinosaurus and Giganotosaurus had died out nearly 30 million years before the impact.

Nearly nine in ten living species of which animals descend from three lineages that boomed after the K-Pg extinction?

Frogs seized the moment: DNA dating shows three lineages burst into new forms right at the boundary, and the tree-climbing families all arose around or after it.

Which plants led the recovery after the K-Pg impact, showing up as a 'spike' in the fossil record?

Ferns bounced back first because their light, wind-borne spores reach bare ground and need no pollinators; a surge of those spores sits just above the impact layer from North America to New Zealand.

Which fossil site in North Dakota appears to record the very hours after the impact?

Tanis was swamped soon after the impact, not by a wave from the distant crater but by river water sloshed inland by earthquake waves that had crossed the continent in minutes.

A 2022 study of growth patterns in fossil fish bones found the asteroid struck in which Northern Hemisphere season?

Spring is what the bones record, in both their growth layers and their chemistry, and the timing may have been cruel: northern animals were breeding while southern ones were settling in for autumn.

Before the Chicxulub crater was confirmed, a sandy bed blamed on the impact's megatsunami was identified in which US state?

Texas's Brazos River holds a sandstone bed that a 1988 study blamed on a giant wave, a clue that steered crater hunters to the region before the crater itself was confirmed.

The last known fossil of a dinosaur species most likely dates from when?

Well before it died out: the odds against the very last animal being fossilised and found are huge, so a sudden extinction can look gradual in the rocks, a trap called the Signor-Lipps effect.

Which Montana rock unit holds the key dinosaur-bearing strata up to the K-Pg boundary?

Hell Creek's mudstones were laid down by rivers and deltas on a mild, forested lowland beside an inland sea, nothing like the dry badlands that expose them in Montana today.

Which organisms briefly flourished on land in the immediate aftermath of the K-Pg catastrophe?

Fungi live on dead matter rather than sunlight, so for a short spell they had the fallen forests to themselves; their spores and threads crowd a thin layer right at the boundary.

Which era began with the K-Pg extinction and continues today?

The Cenozoic is nicknamed the Age of Mammals, though palaeontologists point out it could as fairly be called the age of flowering plants or of insects, which have dominated it just as much.

Which insects, uncommon in the dinosaurs' day, rose to dominance in the Eocene after the K-Pg extinction?

Ants make up only about 1% of insects in Cretaceous fossil deposits; they became common, with far bigger colonies, only in the Eocene, some 20 million years after the impact.

Which fish, known only from fossils of the dinosaurs' era and earlier, was found alive off South Africa in 1938?

The coelacanth's fossil trail stops at the end of the dinosaurs' era, so it was thought to have died out with them until a trawler's net brought one up, steel blue and very much alive.

After mass extinctions like the dinosaurs', species that vanish from the fossil record, then reappear, are named after which biblical figure?

Lazarus, whom Jesus raises from the dead in John's Gospel, lends his name to these 'Lazarus taxa', which reflect gaps in a patchy fossil record rather than true returns from extinction.

Which living reptile is the last survivor of the rhynchocephalians, lizard-like animals once found worldwide?

The tuatara looks like a lizard but is the last of its own ancient order, which thrived alongside the dinosaurs and now survives only on a few dozen New Zealand islands.

Research in October 2019 proposed that the impact rapidly did what to the oceans?

Acidified them: boron traces in fossil plankton shells show the surface ocean turned sharply more acidic after the impact, bad news for the shell-building plankton at the base of the food chain.

The Chicxulub crater takes its name from what?

A nearby town, Chicxulub, gave the name, picked partly, co-discoverer Glen Penfield recalled, to give doubting academics a hard time pronouncing it.

Drilling into the Chicxulub crater's inner ring of hills found it is made of which rock from deep in the crust?

Granite belongs kilometres down, yet the cores show it was heaved up and flung outward within minutes of the impact, coming to rest as a ring of peaks.

The dinosaur-killing asteroid first formed in which part of the solar system?

Beyond Jupiter is where the ruthenium in the boundary clay points: a 2024 study matched it to asteroids born in the outer solar system, unlike the rocks behind five other craters, which formed closer to the Sun.

The Chicxulub impact is often said to have released over a billion times the energy of what?

The Hiroshima atomic bomb is the usual yardstick for a blast put at roughly 100 million megatons, one that shook the ground like an earthquake of magnitude 10 or 11.

Which greenhouse gas, released as the asteroid vaporised limestone, is thought to have warmed the planet for millennia afterwards?

Carbon dioxide lingers for ages: fish fossils from Tunisia suggest the seas there ran about 5°C warmer for some 100,000 years after the impact.