Hadrosaurus: The First Dinosaur Discovered in North America

Hadrosaurus, a notable dinosaur from the Late Cretaceous Period, holds a special place in paleontological history. Recognized as the first dinosaur to be discovered and described in North America, it represents a landmark in the study of cretaceous life. This herbivorous dinosaur offers a fascinating glimpse into an ancient world that thrived millions of years ago.

In this article, I will delve into Hadrosaurus’s key characteristics, its discovery, and the insights gleaned from its fossil evidence. We’ll examine its size, physical description, and the environment it inhabited. I will also include interesting aspects of this dinosaur, as well as answer some frequently asked questions.

Hadrosaurus Key Facts

Meaning of nameFoulke’s Big Lizard
Type SpeciesHadrosaurus foulkii
When it Lived83.6 to 72.1 MYA
PeriodLate Cretaceous
Length23.0 to 26.0 feet
Height10.0 to 12.0 feet
Weight2.2 to 4.4 tons
MobilityMoved on all four
First Discovery1838 by John Estaugh Hopkins
Described by1858 by Joseph Leidy
HolotypeANSP 10005
Location of first findCooper River, Haddonfield, New Jersey

Hadrosaurus Origins, Taxonomy and Timeline

Hadrosaurus, a name derived from Greek words meaning ‘bulky’ or ‘large’ and ‘lizard’, offers a fascinating glimpse into the world of ancient creatures. This name, coined in the mid-19th century, aptly reflects the dinosaur’s significant size and presence.

Hadrosaurus by Audrey.m.horn

Belonging to the Ornithopoda, Hadrosaurus is classified within the hadrosaurid. This categorization places it among a diverse group of herbivorous dinosaurs known for their distinctive features and adaptations. The specific type species of this genus is Hadrosaurus foulkii, a name honoring its discoverer.

The timeline of Hadrosaurus spans in the Late Cretaceous Period, specifically during the Campanian. This places its existence approximately between 83.6 to 72.1 million years ago, a period marked by significant geological and climatic changes.

Hadrosaurus Games

Test (and refresh) your knowledge about Hadrosaurus and other dinosaurs by playing this fun quiz:

Don’t forget to try our other games as well!

Discovery & Fossil Evidence

The tale of Hadrosaurus’s discovery is as fascinating as the dinosaur itself. It all began in 1838, in a marl pit near the Cooper River in Haddonfield, New Jersey, part of the Campanian-age Woodbury Formation. John Estaugh Hopkins, while digging, unearthed large bones that piqued his curiosity. He displayed these intriguing finds at his home in Haddonfield, unknowingly sitting on a historical treasure.

Two decades later, in 1858, these bones caught the attention of William Parker Foulke, a visitor with a keen interest in natural history. Foulke, realizing the potential significance of these remains, initiated a more thorough excavation at the marl pit. This effort led to the unearthing of a more complete skeleton, a discovery that would soon gain monumental importance in the field of paleontology. The excavation site, now known as the Hadrosaurus foulkii Leidy site, has since been recognized as a National Historic Landmark, commemorating this pivotal moment in dinosaur discovery.

The “Second” Discovery

Foulke reached out to the esteemed paleontologist Joseph Leidy, and together, they embarked on a detailed study of the fossils. Their collaborative effort led to the recovery of various parts of the dinosaur, including teeth, fragments of the dental battery, parts of the maxilla, vertebrae, and limb bones. This comprehensive collection of fossils included the left humerus, radius, ulna, and parts of the hindlimb, among others. Their meticulous work laid the foundation for a deeper understanding of this species.

In a remarkable twist of etymological fate, the name Hadrosaurus, initially thought to be a combination of Haddonfield and the suffix ‘-saurus’, was later justified scientifically. Derived from the Greek words ‘hadros’ (meaning ‘bulky’ or ‘large’) and ‘sauros’ (meaning ‘lizard’), it aptly described the dinosaur’s size. Additionally, it served as a clever play on words, translating to ‘Foulke’s Big Lizard’, in honor of William Parker Foulke.

The holotype, ANSP 10005, is a notable specimen that has played a crucial role in the study of Hadrosaurus. The degree of preservation and types of fossils found have allowed scientists to piece together a more comprehensive picture of this dinosaur’s anatomy and behavior.

Hadrosaurus Size and Description

Hadrosaurus, a remarkable dinosaur from the Late Cretaceous Period, presents a unique physical profile. Its robust build sets it apart from other hadrosaurs, hinting at a life adapted to specific environmental challenges. The dinosaur’s anatomy, particularly its beak and teeth, reveals a creature well-equipped for its herbivorous lifestyle.

One of the most striking features of Hadrosaurus is its keratinous beak, an adaptation perfect for cropping foliage. This feature, combined with its specialized and complex dentition, suggests a diet that required significant food processing capabilities. The robust nature of most of its preserved elements, unusual among hadrosaurs, points to a ponderously-built animal, adept at navigating its environment and efficiently consuming the plant life that formed the bulk of its diet.

Size and Weight of Type Species

Size comparison of Hadrosaurus
Slate Weasel, Public domain, via Wikimedia Commons

In terms of size, Hadrosaurus was a large dinosaur, with estimates ranging from 23.0 to 26.0 feet in length. This substantial size is indicative of its prominent role in the ecosystems of the Late Cretaceous Period. When it comes to weight, Hadrosaurus tipped the scales at an impressive 2.2 to 4.4 tons. This considerable heft further underscores its robust and sturdy build, a characteristic that likely played a crucial role in its survival and dominance during its time.

The combination of its size, weight, and unique physical features paints a picture of a dinosaur that was not only a significant presence in its habitat but also a fascinating subject for study in the field of paleontology. Hadrosaurus’s adaptations, from its beak to its teeth, offer insights into the evolutionary paths taken by herbivorous dinosaurs and their interactions with the environment millions of years ago.

Contemporary Dinosaurs

In the world of the Late Cretaceous, a Hadrosaurus roamed, a magnificent creature that was a sight to behold. Amidst the dense foliage and towering trees, this gentle giant, larger than a city bus, ambled along on its powerful hind legs. Its life was a constant quest for the juiciest leaves and the tenderest shoots. But this journey wasn’t a solitary one. Hadrosaurus shared its world with a cast of contemporaries, each playing a unique role in the tapestry of their ancient ecosystem.

Picture this: a serene lakeside, where our Hadrosaurus often wandered to quench its thirst. Here, it might encounter the elegant Tsintaosaurus, a fellow duck-billed dinosaur. Tsintaosaurus, with its distinctive crest, was roughly the same size as our Hadrosaurus. These peaceful herbivores likely coexisted harmoniously, perhaps even moving in herds together, their calls and honks creating an ancient symphony. They shared a bond, not just in their diet, but in the way they navigated their world, always alert for danger.

But life wasn’t all serene for our Hadrosaurus. The presence of Hypacrosaurus, another contemporary, hinted at a subtle competition. Similar in size and diet, these two might have vied for the best grazing spots or nesting areas. Imagine the tension during the breeding season, with both species trying to claim the safest and most abundant areas for their young. Yet, despite this rivalry, there was a kind of respect, an understanding that each had a role to play in the delicate balance of their environment.

Then there were Corythosaurus and Lambeosaurus, other members of the Hadrosaur family. These dinosaurs, with their distinctive crests and calls, were like distant cousins to our Hadrosaurus. They likely interacted occasionally, perhaps at large water sources or while migrating. These interactions, whether competitive or cooperative, were crucial in the life of our Hadrosaurus, shaping its behavior, its movements, and its very survival. In this ancient world, every day was an adventure, a challenge, and a testament to the resilience and adaptability of these incredible creatures.

Interesting Points about Hadrosaurus

Hadrosaurus in its Natural Habitat

Hadrosaurus thrived in a world vastly different from ours. During the Late Cretaceous Period, the climate was warmer, and the geography was marked by extensive coastal plains and lush vegetation. This environment provided an ideal habitat for a large herbivore like Hadrosaurus.

As a herbivore, Hadrosaurus’s diet would have consisted primarily of the abundant plant life of its time. Its mobility, whether on two legs or all four, would have played a crucial role in its ability to forage and navigate its environment. Hadrosaurus’s social behavior, whether as a solitary creature or a herd animal, also contributes to our understanding of its lifestyle and interactions within its ecosystem.

The impact of Hadrosaurus on its environment cannot be understated. As a large herbivore, it would have shaped the landscape through its feeding habits and movements, playing a vital role in the ecological dynamics of its time.

Frequently Asked Questions

When was this dinosaur first discovered?

It was first discovered in 1838 by John Estaugh Hopkins near the Cooper River in Haddonfield, New Jersey.

What does its name mean?

The name means “Foulke’s Big Lizard,” reflecting its significant size and the name of its discoverer.

What type of diet did it have?

As a herbivore, its diet consisted primarily of plants.

Where else have fossils been found?

Fossils have also been found in Kazakhstan, Mississippi, North Carolina, and Alberta.

What period did it live in?

It lived during the Late Cretaceous Period, approximately 83.6 to 72.1 million years ago.

What is unique about its mobility?

It likely moved on all four.


The information in this article is based on various sources, drawing on scientific research, fossil evidence, and expert analysis. The aim is to provide a comprehensive and accurate overview of Hadrosaurus. However, please be aware that our understanding of dinosaurs and their world is constantly evolving as new discoveries are made.

This article was last fact-checked: Joey Arboleda, 11-29-2023

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