The Hadrosaurus was the first dinosaur to be scientifically described and identified in 1858 in North America. It has been referred to as a nomen dubium, or “doubtful name” because only a small amount of fossil material has been found. Based on the fossil remains it was large, bulky, and heavily built and had a long neck and tail and a beak. It was a herbivore and is thought to have lived in herds during the Upper Cretaceous period some 80-78 million years ago.

Key Facts

Hadrosaurus pronunciationHad-roe-sore-us
What does the name mean?Bulky Lizard
Dinosaur typeOrnithopod
On the menuHerbivorous
Length30 feet (9 meters)
Height10 feet (3 meters)
Weight6500 lbs (3 tons)
Life expectancyUnknown
Legs used to get aroundQuadruped
Estimated top speedUnknown
When they livedUpper Cretaceous, 80-78 million years ago
Where they have been found?USA

When & Where

In 1938, John Estaugh Hopkins was digging a mudhole on his family’s property in New Jersey when he discovered some bones. These turned out to be fossils of Hadrosaurus foulkii. They were officially described in 1858 by Joseph Leidy, and a skeleton was mounted in 1868 to become the first dinosaur on public display in North America.

This initial imagined appearance turned out to be inaccurate, as it was based on incomplete fossil evidence. It wasn’t until the 1990s that scientists had a complete idea of what Hadrosaurus looked like, thanks to better fossil discoveries. The type species is Hadrosaurus foulkii, named after William Parker Foulke, who discovered some fossils in 1858.

Size & Weight

The Hadrosaurus was a large, bulky, and heavily built dinosaur. It was roughly 30 feet long, 10 feet tall, weighing approximately 3 tons (just about the same mass as a modern-day hippo).

Mobility & Diet

The Hadrosaurus was quadrupedal, meaning it got around on four legs. It is thought to have been an herbivore that lived in herds. This herding behavior is often seen in animals that are preyed upon, as there is safety in numbers.

Interesting Points

  • Hadrosaurus was the first named hadrosaurid. (The name of the group of dinosaurs is always derived from the name of the first member to be identified and described.)
  • The Hadrosaurus was the first-ever dinosaur to be scientifically described and identified.
  • The Hadrosaurus was initially described as a biped in early reconstructions, but we now know that it was quadruped.
  • It is the only known hadrosaurine to date – a classification of solid crested hadrosaurids.
  • Hadrosaurus was the official state dinosaur of New Jersey from 1991-2007.
  • The skull of the Hadrosaurus remains unknown, as only the bones of the lower jaw have been found.
  • The Hadrosaurus was most likely preyed on by large theropods, such as the Tyrannosaurus and giant crocodiles, which also lived during the Late Cretaceous.

Featured Image Credit: Audrey.m.horn, CC BY-SA 4.0, via Wikimedia Commons