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The dinosaurs

They ruled the land for more than 160 million years, came in every size, and never really went away. Look up at the birds.

For more than 160 million years, the largest animals on land were dinosaurs. They appear in the rocks about 230 million years ago, in the Late Triassic. Some of the earliest, such as Eoraptor from Argentina, were two-legged animals about 1.7 metres long. After a mass extinction at the end of the Triassic, 201 million years ago, the dinosaurs took over.

The age of the dinosaurs takes up three periods of geological time, which together make the Mesozoic era: the Triassic, the Jurassic and the Cretaceous. The Cretaceous alone lasted about 77 million years, longer than the time since it ended.

Further apart than you think

Dinosaurs are often drawn together, as if they all lived at once. They did not. Stegosaurus lived in what is now the western United States between about 152 and 145 million years ago. Tyrannosaurus lived between about 68 and 66 million years ago. That means more time passed between the last Stegosaurus and the first Tyrannosaurus than has passed between the last Tyrannosaurus and you.

A timeline from 160 million years ago to today. Stegosaurus sits near the left, between 152 and 145 million years ago. Tyrannosaurus sits at 68 to 66 million years ago, near the middle. The gap between them, about 77 million years, is longer than the gap from Tyrannosaurus to today, 66 million years.NeogenePaleogeneCretaceousJurassicStegosaurusTyrannosaurusYou77 million years66 million years150 Ma100 Ma50 Manow
The green gap is longer than the red one.Our own sum, from the Natural History Museum's dates and the ICS chart

Every size

The smallest dinosaurs in the museum's records were 30 to 50 centimetres long. The biggest were long-necked sauropods such as Patagotitan, which the museum puts at about 37.5 metres long. Here are seven of them on the same scale, each beside a person 1.75 metres tall.

All drawn to one scale, 40 metres across. The red figure is a person.Lengths from the Natural History Museum; body shapes drawn for this site

Found in England first

People had been digging up dinosaur bones for centuries without knowing what they were. In 1824 William Buckland described a huge meat-eater from the Stonesfield Slate in Oxfordshire and named it Megalosaurus. Soon after came Iguanodon and Hylaeosaurus, also from England. In 1842 the anatomist Richard Owen grouped these three together and gave them a new name: the Dinosauria.

Since then the pace of discovery has grown and grown. Of the dinosaurs in the museum's directory, more were named in the 1990s than in the whole of the 1800s.

A bar chart of how many of the dinosaurs in the Natural History Museum's directory were named in each decade, from the 1820s to the 2000s. There are only a handful each decade in the 1800s, a peak in the 1910s and 1920s, a lull in the 1940s, and then far more from the 1970s on, with about fifty each in the 1990s and 2000s.1820s: 11820s1830s: 31840s: 11850s: 61850s1860s: 51870s: 91880s: 71880s1890s: 61900s: 91910s: 231910s1920s: 241930s: 151940s: 51940s1950s: 101960s: 101970s: 401970s1980s: 371990s: 512000s: 502000sDinosaurs named each decade, of the 326 in the museum's directory
Most of the dinosaurs we know were named in the last fifty years.Counted by us from the Natural History Museum's Dino Directory, to 2009; the directory lists few dinosaurs named since

Dinosaurs of Britain

22 of the dinosaurs in the museum's directory have been found in Britain, and here they all are. Read about each one in the dinosaur encyclopaedia.

They never really left

Sixty-six million years ago an asteroid about 10 km across struck what is now Mexico. The dinosaurs died out, along with about three quarters of all species. All but one branch. Birds come from the theropods, the same group of two-legged dinosaurs as Tyrannosaurus and Velociraptor. Many features of living birds appeared in dinosaurs long before the first birds, and the slow change from running theropods to flying birds probably started about 160 million years ago. The pigeon on your windowsill is a living dinosaur.

About 230 millionYears since the first dinosaurs
37.5 mPatagotitan, the longest in the museum's records
1842The year the word dinosaur was coined, in London
22Dinosaurs in the directory found in Britain