Dippy the Diplodocus: Andrew Carnegie's Dinosaur and Its Casts

Dippy the Diplodocus is the popular name for the plaster casts of Diplodocus carnegii, a long-necked dinosaur whose fossils were found in Wyoming in 1899 by an expedition paid for by the steel magnate Andrew Carnegie. In 1905 a full-size cast was unveiled in London, and over the following years Carnegie presented copies to museums across Europe and Latin America. Dippy became one of the most familiar dinosaurs in the world and helped turn the public’s fascination with dinosaurs into a global phenomenon.

Background: Carnegie and the “most colossal animal”

By the late 1890s Andrew Carnegie, the Scottish-born industrialist, was one of the richest men in the world and was funding the Carnegie Institute in Pittsburgh, including a new natural history museum. In late 1898 newspapers carried sensational reports of a gigantic dinosaur found in Wyoming, described as the most colossal animal ever on Earth.

Carnegie was captivated. He gave money to the museum’s director, William Jacob Holland, to send collectors to the West and find a giant sauropod for Pittsburgh. The rocks of the Morrison Formation in Wyoming had been made famous two decades earlier by the Bone Wars between Edward Drinker Cope and Othniel Charles Marsh, who had named Diplodocus in 1878.

The 1899 discovery

The Carnegie Museum’s field crew included the experienced collector William Harlow Reed, who had worked for Marsh at Como Bluff, and the palaeontologist Jacob Wortman. After an unpromising start, the team began working at Sheep Creek in Albany County, Wyoming. On 4 July 1899, American Independence Day, they found the remains of a large sauropod.

The specimen, catalogued as CM 84, included a large part of the vertebral column, ribs, pelvis and limb bones. A second partial skeleton, CM 94, was found nearby in 1900. Together they formed the basis for the Pittsburgh reconstruction, with gaps filled from other specimens and by careful modelling.

In 1901 the palaeontologist John Bell Hatcher, then working for the Carnegie Museum, described the find as a new species and named it Diplodocus carnegii in honour of its patron. His detailed monograph also included a restoration of the complete skeleton.

From Pittsburgh to London

A drawing of the restored skeleton hung at Skibo Castle, Carnegie’s estate in the Scottish Highlands. According to the widely told story, King Edward VII saw it on a visit and expressed a wish for such a dinosaur for the British Museum’s natural history collections. Carnegie offered a full-size cast rather than the original.

Making the cast was a large undertaking. Moulds were taken from the bones in Pittsburgh, and plaster replicas were produced under the direction of the preparator Arthur Coggeshall. The 292 pieces were shipped to London in 36 crates, and Coggeshall travelled with them to supervise the mounting.

The cast was unveiled at the British Museum (Natural History) in South Kensington on 12 May 1905, with Carnegie present. It drew huge crowds and enormous press attention. The original fossils were only mounted in Pittsburgh in 1907, so Londoners saw the complete skeleton before Americans did.

Casts around the world

The London success led to requests from other countries, and Carnegie used the casts as a form of cultural diplomacy, linked to his campaigning for international peace. Holland and Coggeshall travelled to install casts in Berlin and Paris in 1908, then in Vienna and Bologna in 1909, St Petersburg in 1910, La Plata in Argentina in 1912 and Madrid in 1913. A further cast went to Mexico City in 1930, after Carnegie’s death in 1919.

The presentations were often marked by official ceremonies, and the gifts were reported in newspapers across Europe and the Americas. Several casts survived the world wars, and most remain on display, from the Museum für Naturkunde in Berlin to the Museo de La Plata in Argentina.

The casts helped standardise the image of a sauropod in the public mind: a vast animal with a tiny head, long neck and longer tail. Through them, Diplodocus became for many Europeans the archetypal dinosaur, alongside the later Berlin sauropod from the Tendaguru excavations.

What kind of animal was Diplodocus?

Diplodocus was a sauropod, one of the long-necked, plant-eating dinosaurs that were the largest animals ever to walk on land. It lived in the Late Jurassic, roughly 154 to 150 million years ago, on the floodplains of western North America, alongside Apatosaurus, Stegosaurus and the predator Allosaurus.

Despite its great length, Diplodocus carnegii was relatively slender. Modern weight estimates vary widely but are often given in the range of about 10 to 15 tonnes, far lighter than bulkier sauropods. Its long tail tapered to a thin, whip-like end, and its small skull carried narrow, peg-like teeth at the front of the jaws, suited to stripping leaves and soft plants rather than chewing.

How Diplodocus held its neck remains debated. Some studies suggest it was carried fairly low and swept from side to side to browse over a wide area; others argue it could be raised higher. The name itself, coined by Marsh, means “double beam”, referring to unusual paired bony struts under the tail vertebrae.

Dippy in London

In London the cast was first displayed in the museum’s Reptile Gallery. During the Second World War it was dismantled and stored in the basement to protect it from bombing. In 1979 it moved to the museum’s great central hall, now called Hintze Hall, where it greeted generations of visitors.

Science moved on around it. Early reconstructions showed the tail dragging on the ground, but by the 1990s palaeontologists agreed that sauropods held their tails clear of the ground. In 1993 the museum repositioned Dippy’s tail to curve upwards in a more active pose.

In January 2017 Dippy was taken down and replaced in Hintze Hall by the real skeleton of a blue whale, nicknamed Hope. The decision was controversial with some visitors, but the museum wanted its central display to be a real specimen with a conservation message. From 2018 Dippy went on tour, visiting venues including Dorset, Birmingham, Belfast, Glasgow, Newcastle, Cardiff, Rochdale and Norwich.

By the numbers

Timeline

• 1878: Othniel Charles Marsh names the genus Diplodocus.
• 1898: Andrew Carnegie funds a search for a giant dinosaur for his Pittsburgh museum.
• 1899, 4 July: The Carnegie crew finds the main specimen at Sheep Creek, Wyoming.
• 1901: John Bell Hatcher names Diplodocus carnegii.
• 1905, 12 May: The first full-size cast is unveiled in London.
• 1907: The original skeleton is mounted in Pittsburgh.
• 1908–1913: Casts are installed in Berlin, Paris, Vienna, Bologna, St Petersburg, La Plata and Madrid.
• 1979: Dippy moves to the museum’s central hall in London.
• 2017, January: Dippy is replaced by the blue whale skeleton and later goes on a UK tour.

Why it matters

Dippy shows how a single fossil find, backed by private wealth, could shape popular culture across continents. Carnegie’s casts made dinosaurs a shared public spectacle in cities that had never seen one, and they set a pattern for museums using replicas to bring rare specimens to wider audiences. More than a century later, Dippy remains one of the best loved museum objects in Britain.