Everything we know about dinosaurs comes from physical evidence preserved over millions of years - bones, teeth, footprints, eggs, skin impressions, and even fossilized droppings. These remains have survived in the world's deserts, riverbeds, and cliff faces. It was not until the 19th century that scientists correctly identified them as belonging to extinct giant reptiles, and the science of palaeontology was born. Since then, fossils have been unearthed on every continent - including Antarctica - and new species are still being discovered at a rate of around 50 each year.
A fossil is the preserved remains, or trace, of a living thing that died long ago. Body fossils include bones, teeth, shells, and occasionally even skin or feather impressions. Trace fossils include footprints, burrows, nests, and coprolites (fossilized droppings). One of the most common fossils is the ammonite, a coil-shelled sea creature that swam in the oceans during the age of the dinosaurs. Ammonites became extinct at the same time as the dinosaurs, around 66 million years ago.
Ammonite
People had been collecting strange bones for centuries, often calling them the remains of giants or dragons. The first dinosaur to be scientifically described was Megalosaurus, named in 1824 by the English geologist William Buckland from a fossilized jaw found in Oxfordshire. By 1842, the anatomist Sir Richard Owen realized that Megalosaurus, Iguanodon, and Hylaeosaurus all belonged to a single unique group of extinct reptiles. He gave them the name Dinosauria - meaning "terrible lizards" - and modern dinosaur science was born.
Megalosaurus Jaw
Palaeontologists are scientists who study fossils to reconstruct ancient life. Their work takes them from windswept fossil sites in deserts, mountains, and quarries to clean, well-lit laboratories where each bone is painstakingly prepared. In the field, palaeontologists use tools like rock hammers, brushes, dental picks, and plaster jackets to remove fragile fossils from the surrounding stone. In the lab, they use microscopes, CT scanners, and computer models to study internal structures and even estimate how a dinosaur moved, fed, or grew. Famous palaeontologists include Mary Anning, Roy Chapman Andrews, Jack Horner, and Paul Sereno.
Palaeontologists
Most dinosaur skeletons on display in museums are not made entirely of real fossils. Complete dinosaur skeletons are extraordinarily rare, so palaeontologists usually create museum mounts from a mix of real bones and synthetic casts. Each bone is carefully scanned or moulded, then duplicated in lightweight resin or fibreglass and painted to match. A metal frame supports the assembled skeleton from the inside or behind. This approach protects the precious real fossils, which are usually kept safely in research collections, while still giving visitors a life-sized look at the animal.
Tuojiangosaurus
Most dinosaur names are formed from Greek or Latin roots and describe something noteworthy about the animal. Some are named after a physical feature: Triceratops means "three-horned face," Stegosaurus means "roof lizard," and Pachycephalosaurus means "thick-headed lizard." Others are named for the place they were found: Argentinosaurus means "reptile of Argentina," and Albertosaurus takes its name from Alberta in Canada. A few honour the person who discovered them - Herrerasaurus was named after the rancher Victorino Herrera, who spotted its bones in Argentina in 1959.
Triceratops
Fossils are formed by a slow process called mineralization, which usually takes thousands to millions of years. Most dinosaur fossils are found in former riverbeds, lake beds, or floodplains - places where a body could be quickly covered by sand or mud before it rotted away. Soft tissues decay first, leaving the bones behind. Mineral-rich water then seeps through the bones, gradually replacing the original material with hard minerals like silica or calcite. Over time, the bones turn to stone. Much later, erosion may expose them, and a sharp-eyed palaeontologist may spot a fragment poking out of a cliff or hillside.
Palaeontologist at a dig site