Hypacrosaurus: Unveiling the Secrets of a Late Cretaceous Herbivore

Hypacrosaurus, a dinosaur from the Late Cretaceous Period, presents a fascinating chapter in the history of our planet. This herbivorous species, whose name translates to “Near the Highest Lizard,” offers a unique window into a world that existed millions of years ago. First discovered in the early 20th century, Hypacrosaurus has since been a subject of intrigue and study among paleontologists.

Belonging to the Ornithopoda and classified within the hadrosaurid, Hypacrosaurus roamed the earth approximately between 83.5 and 66.0 million years ago. Its discovery in Alberta, Canada, and subsequent findings in Montana have provided valuable insights into its existence and the environment it inhabited. As we delve into the details of this remarkable dinosaur, we uncover more about the diverse and dynamic ecosystems of the Late Cretaceous Period.

Hypacrosaurus Key Facts

Meaning of nameNear the Highest Lizard
Type SpeciesHypacrosaurus altispinus
Other SpeciesHypacrosaurus stebingeri
When it Lived73.2 to 66.0 MYA
PeriodLate Cretaceous
EpochCampanian and Maastrichtian
Length30.0 feet
HeightApproximately 11.0 feet
Weight4.4 tons
MobilityMoved on two legs
First Discovery1910 by Barnum Brown
Described by1913 by Barnum Brown
HolotypeAMNH 5204
Location of first findRed Deer River, Tolman Ferry Member, Horseshoe Canyon Formation, Alberta, Canada
Also found inMontana

Hypacrosaurus Origins, Taxonomy and Timeline

Hypacrosaurus, deriving its name from Greek roots meaning “near the highest lizard,” offers a window into the Late Cretaceous Period. This nomenclature not only underscores its impressive stature but also subtly distinguishes it from the apex species of its era.

Life reconstruction of Hypacrosaurus altispinus
Connor Ashbridge, CC BY-SA 4.0, via Wikimedia Commons

Taxonomically, Hypacrosaurus falls within the Ornithopoda, under the hadrosaurid group. This classification places it among herbivorous dinosaurs known for specialized dental structures. Within this genus, there are two notable subspecies: the type species, Hypacrosaurus altispinus, and Hypacrosaurus stebingeri. The former is known from several articulated skulls and skeletal remains, ranging from juveniles to adults, found in the Horseshoe Canyon Formation. The latter, H. stebingeri, is distinguished by a substantial number of individuals, from embryos to adults, with its remains discovered in the Two Medicine Formation in Montana and Alberta. These findings, particularly of H. stebingeri, include the largest collection of baby skeletal material of any single species of Hadrosaur known.

The relationship between H. altispinus and H. stebingeri has been a topic of scientific discourse. Initial hypotheses suggesting a close relationship between the two were challenged by studies indicating a closer phylogenetic link between Nipponosaurus and H. altispinus. However, this view was later contested, highlighting the complexity and evolving nature of dinosaur taxonomy.

Hypacrosaurus thrived during the Campanian and Maastrichtian, approximately 73.2 to 66.0 million years ago. This period was characterized by significant environmental changes, shaping the evolutionary journey of Hypacrosaurus and its contemporaries. The ongoing study of these subspecies continues to shed light on the diverse and dynamic ecosystems of the Late Cretaceous.

Listen to Pronunciation

If you are curious about this dinosaur’s name you can listen to it here.

Discovery & Fossil Evidence

The type remains of this species were collected in 1910 by the renowned Barnum Brown for the American Museum of Natural History. These initial remains, consisting of several vertebrae and a partial pelvis, were unearthed near the Red Deer River in Alberta, Canada, within the Horseshoe Canyon Formation. At that time, the absence of a skull in these findings left some questions about the dinosaur’s complete anatomy.

Brown’s initial description in 1913, which likened Hypacrosaurus to Saurolophus, was soon complemented by the discovery of two skulls. These crucial finds helped to paint a more complete picture of the dinosaur, contributing significantly to our understanding of its physical structure.

The early 20th century saw numerous discoveries of small, hollow-crested duckbills, initially thought to be distinct genera and species. Among these was Cheneosaurus tolmanensis, identified from a collection of skull, limb, vertebral, and pelvic bones in the same Horseshoe Canyon Formation. Another notable discovery was a skeleton in the Two Medicine Formation of Montana, initially classified as Procheneosaurus. For a time, these finds were considered separate entities.

However, the 1970s brought a shift in perspective, thanks to the work of paleontologist Peter Dodson. Dodson proposed that these so-called “Cheneosaurs” were likely juvenile forms of other established Lambeosaurines, including the Hypacrosaurus altispinus. This hypothesis, suggesting a developmental link between Cheneosaurus and Hypacrosaurus, gained acceptance, although it wasn’t formally tested. Furthermore, the Two Medicine Procheneosaurus specimen, distinct from others, bore a closer resemblance to what would later be identified as H. stebingeri, named in 1994.

These discoveries and subsequent analyses have been instrumental in shaping our understanding of Hypacrosaurus. They highlight not only the complexity of dinosaur taxonomy but also the evolutionary and developmental nuances within these magnificent creatures.

Hypacrosaurus Size and Description

Hypacrosaurus, a member of the hollow-crested duckbills known as Lambeosaurines, stands out due to its distinctive physical features. One of the most striking characteristics of this dinosaur is its tall neural spines. These spines, projecting from the vertebrae, are about 5 to 7 times the height of the vertebrae’s body in the back, giving Hypacrosaurus a notably tall back when viewed in profile.

The skull of Hypacrosaurus is adorned with a hollow crest, somewhat similar to that of Corythosaurus but with its own unique traits. This crest is more pointed at the top, not as tall, and broader side to side compared to its Corythosaurus counterpart. Additionally, it features a small bony point at the rear. Unlike other Lambeosaurines, the airway passages in the crest of H. altispinus do not form an S-curve, marking another distinctive aspect of its anatomy.

Apart from these features, the skeleton of Hypacrosaurus does not present many extraordinary attributes. However, some details in the pelvic area are distinctive. Like other duckbills, it was capable of moving both bipedally and quadrupedally, adapting its locomotion as needed.

Size and Weight of Type Species

Size comparison of the two species Hypacrosaurus, a genus of lambeosaurine hadrosaur from the Upper Cretaceous of North America.
Slate Weasel, Public domain, via Wikimedia Commons

Hypacrosaurus was a considerable presence in its habitat, with an estimated length of around 30.0 feet. In terms of weight, this dinosaur is believed to have tipped the scales at up to 4.4 tons. These dimensions place it among the larger herbivores of its time, capable of making a significant impact on its environment.

The two known species of Hypacrosaurus, H. altispinus and H. stebingeri, are not differentiated by typical unique characteristics. H. stebingeri, in particular, is described as transitional between the earlier Lambeosaurus and the later Hypacrosaurus. This transitional nature adds an intriguing layer to our understanding of the evolutionary progression within the Lambeosaurines.

Contemporary Dinosaurs

Restoration of H. altispinus in environment
ABelov2014, CC BY 3.0, via Wikimedia Commons

Hypacrosaurus, larger than a school bus, roamed through the ancient forests with a certain majestic grace. Its life was a constant dance of coexistence and competition with its contemporaries like Corythosaurus, Lambeosaurus, Parasaurolophus, and Prosaurolophus. These dinosaurs, all part of the hadrosaur group, shared a similar lifestyle, but each had its unique flair. Hypacrosaurus, with its striking crest, was like the orchestra conductor among its peers, leading a symphony of survival and adaptation.

Imagine a scene by a vast Cretaceous river: our Hypacrosaurus, a gentle giant, is grazing peacefully. Nearby, a Corythosaurus, slightly smaller but just as impressive with its helmet-like crest, is also feasting on the lush vegetation. They coexist somewhat amicably, but there’s an unspoken competition for the choicest greens. Lambeosaurus, with its hatchet-shaped crest, joins the feast, adding to the dynamic interplay of these ancient creatures. They are like different musicians playing the same tune, each adding their unique note to the melody of life back then.

But life wasn’t all peaceful grazing for our Hypacrosaurus. The threat of predators loomed large. While it was not the primary target due to its massive size, younger or weaker members of its herd could fall prey to the fearsome Theropods of the time. Parasaurolophus, with its long, curved crest, might have been a more frequent target, being roughly the same size but perhaps less robustly built than our main dinosaur. Prosaurolophus, smaller and less imposing, might have been an easier catch for predators, constantly reminding Hypacrosaurus of the dangers lurking in the shadows.

In this ancient world, Hypacrosaurus didn’t just exist; it played a pivotal role in the ecosystem. Its interactions with contemporaries like Corythosaurus and Lambeosaurus highlighted the competitive yet co-dependent nature of their existence. The presence of predators added a layer of complexity, shaping the behavior and evolution of these magnificent creatures. Hypacrosaurus, with its grand stature and commanding presence, was not just a passive participant but a central figure in the tapestry of its Cretaceous world.

Interesting Points about Hypacrosaurus

Hypacrosaurus in its Natural Habitat

Hypacrosaurus thrived in a world vastly different from ours. During the Late Cretaceous, the landscape was dominated by lush vegetation, with a climate that varied from region to region. This herbivore’s diet consisted primarily of plants, which it was well-equipped to process with its specialized teeth and jaws.

As a bipedal creature, Hypacrosaurus could have navigated its environment with relative ease, moving between feeding areas and possibly avoiding predators. Its role in the ecosystem was significant, likely influencing the types of vegetation that thrived and the overall landscape.

Social behavior in Hypacrosaurus is not definitively known, but like many hadrosaurids, it might have exhibited herd behavior. Living in groups could have offered advantages in terms of food sourcing and protection from predators. The sensory capabilities of Hypacrosaurus, while not fully understood, would have been crucial in navigating its complex ecosystem.

Frequently Asked Questions

What did this dinosaur eat?

Hypacrosaurus was a herbivore, primarily feeding on the lush vegetation of the Late Cretaceous Period.

How did it move around?

It was primarily bipedal, moving on two legs, though it could have used all four for certain activities.

Where were its fossils first discovered?

Its fossils were first discovered near the Red Deer River in Alberta, Canada, in 1910.

What is unique about its physical appearance?

Hypacrosaurus had a distinctive cranial crest, which might have been used for social signaling or sound production.

Did it live alone or in groups?

While not definitively known, it is possible that, like many hadrosaurids, the Hypacrosaurus lived in herds.

What does its name mean?

Its name means “Near the Highest Lizard,” a reference to its impressive stature.


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 Hypacrosaurus. 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, 12-06-2023

Featured Image Credit: Nobu Tamura, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons