The duck-billed dinosaur

  • Name: Hypacrosaurus
  • Diet: Herbivore
  • Weight: 4 tons
  • Period: Cretaceous
  • Found In: North America

Hypacrosaurus received its strange name because, when it was discovered in 1910, this duck-billed dinosaur was considered the second one after the size of Tyrannosaurus Rex.

What does the name Hypacrosaurus mean?

Hypacrosaurus derives its name from its interesting physical appearance. It means “under the upper lizard” and was a large duck-like, herbivorous, plant-eating dinosaur (a hadrosaur) similar to Corythosaurus.

It was about 30 feet long, had almost 40 rows of cheeks, a short toothless beak and a row of short spines protruding from its vertebrae, forming a small flipper along its back.

History of the discovery of Hypacrosaurus

Fossils (mainly skulls) have been found in Alberta, Canada and Montana, USA. Hypacrosaurus was originally found by fossil hunter Barnum Brown near Tolman Ferry (near Alberta, Canada) in 1912. Brown named it in 1913.

From then on, many investigations were carried out in order to find more information about this interesting dinosaur, finding a very striking aspect like the following:

Hypacrosaurus eggs

A nest that may have belonged to Hypacrosaurus was found in Devil’s Coulee, near Alberta, Canada. The nest had eight large round eggs, plus the bones of duck-billed embryos, probably those of Hypacrosaurus. The melon-sized eggs were laid in rows and probably covered with sand and plant material.

Classification of Hypacrosaurus

Hypacrosaurus was an ornitischian dinosaur, the order of the herbivorous dinosaurs with the wings of a bird. It was an Ornithopod (bipedal, bipedal, bipedal herbivorous dinosaurs), a hadrosaur (the duck-billed dinosaurs) and a Lambeosauridae (hollow-crested duck beads, which also includes Bactrosaurus, Corythosaurus, Lambeosaurus Parasaurolophus

When and where did the Hypacrosaurus live?

Hypacrosaurus lived during the Cretaceous period, approximately 72 to 70 million years ago, towards the end of the Mesozoic right in the Age of Reptiles.

Among the contemporaries of Hypacrosaurus at the end of the Cretaceous (in North America) were Albertosaurus, Corythosaurus, Nanotyrannus, Parasaurolophus, Euoplocephalus, Kritosaurus and Pachyrhinosaurus.


What did the Hypacrosaururs eat?

Hypacrosaurus was an herbivore, it ate pine needles, seeds, fruits, twigs and magnolia leaves.

Hypacrosaurus description

Like most other hadrosaurs, Hypacrosaurus was distinguished by the prominent ridge on its snout (which did not reach the baroque shape and size of the Parasaurolophus ridge).

This ridge was a resonance device to channel air blasts, warn about their sexual availability, or to warn the herd about approaching predators.

He lived mainly in the forests of North America, where he made his living. Some studies have determined that it climbed to the highest areas, where it made sounds to highlight mating signals.

This dinosaur was an ornithopod, whose intelligence (measured by its brain relative to body weight, or EQ) was halfway among the most prominent dinosaurs.

It walked and ran on two legs, and was a relatively fast dinosaur. It may have gone on all fours just to look for ground plants.

It may also have been a grazing animal. It lived in rainforests and may have migrated from the coast to higher ground to breed.

General Hypacrosaurus characteristics:

  • It had a hollow, bony crest on the top of its long head in the form of a flattened hoof on the sides (like the crest of Corythosaurus but thicker). The nostrils of Hypacrosaurus were seen through the ridge.
  • The ridge may have been used to make sounds, as a cooling device, courtship displays, or as an olfactory enhancer.
  • Males had larger crests than females and juveniles.
  • It had a toothless beak and hundreds of cheeks which it used to grind up its food.
  • It walked on two legs, had shorter arms and a long, heavy tail.
  • It had no natural defences.
  • Its size and weight was about 30 feet long and 4 tons

Curiosities about Hypacrosaurus

What sets Hypacrosaurus apart from most other hadrosaurs is the discovery of a complete nesting ground, complete with fossilized eggs and young (similar evidence has been found for another North American duck-billed dinosaur, Maiasaura).

Hypacrosaurus Highlights

This important highlight has allowed paleontologists to gather a good deal of information about the growth patterns and family life of Hypacrosaurus: for example, it is known that the young of Hypacrosaurus reached adult size in 10 or 12 years, much earlier than the typical 20-30 year-old Tyrannosaurus.

Each of these important aspects makes the Hypacrosaurus an interesting dinosaur, so it is worth an analysis of it to continue learning its details and characteristics.