Fun Acristavus Facts For Kids

The Acristavus gagslarsoni was a species of a hadrosaur that inhabited the continent of North America in the Campanian age of the Late Cretaceous period. The discovery of two specimens of this species has been made so far, one in the Two Medicine Formation in Montana in 1999 and the other in the Wahweap Formation of Utah in 2011. Due to its unique characteristic of not having any cranial ornamentation despite being a hadrosaur, it has been given the name 'non-crested grandfather.' Due to this, it has been thought to be a primitive ancestor of other hadrosaurids such as the Parasaurolophus, Brachylophosaurus, and Maiasaura.

To learn more about this roar-some reptile, read on! For more relatable content, check out these Nqwebasaurus facts and Loricatosaurus facts for kids.

How do you pronounce 'Acristavus'?

Acristavus can be pronounced as 'Ak-riss-ta-vus.'

What type of dinosaur was an Acristavus?

Acristavus was a member of the hadrosaur i.e. a duck-billed dinosaur family, though unlike most hadrosaurs it did not possess any ornamentation on its skull. It existed during the Campanian era of the Late Cretaceous period.

In which geological period did the Acristavus roam the Earth?

The Acristavus dinosaur roamed the Earth around the time of the Campanian age of the Late Cretaceous period, which lasted from around 83.6-72.1 million years ago.

When did the Acristavus become extinct?

The Acristavus dinosaurs mostly all died out by the end of the Campanian age, which ended around 72.1 million years ago.

Where did an Acristavus live?

The discovery of the two known Acristavus remains was made in the continent of North America, one in the Two Medicine Formation in Montana and the other in the Wahweap Formation of Utah.

What was an Acristavus' habitat?

The Acristavus most likely lived among the plains. Due to it being herbivorous in nature, it would have lived in an environment where vegetation was dense and water abundantly available.

Who did an Acristavus live with?

Acristavus, like most other dinosaurs, mostly lived in packs. There are high chances of herbivorous dinosaurs living and feeding together in groups, and this theory has been developed due to the discovery of a number of fossilized trackways containing a sequence of dinosaur footprints, all suggesting the presence of dinosaurs traveling in groups.

How long did an Achelousaurus live?

Though the exact lifespan of a dinosaur cannot be determined, it has been estimated that they lived quite long lives, akin to those of similar reptiles like crocodiles and turtles. Due to their slow metabolisms and herbivorous diets, these beasts have been estimated to live between 80-300 years.

How did they reproduce?

Acristavus dinosaurs were oviparous and reproduced by laying eggs. Their mating process was mostly similar to that of modern-day reptiles, with internal fertilization taking place inside the female's body.

What did an Acristavus look like?

The Acristavus most likely looked like other hadrosaurs. Hadrosaurs had bulky bodies with thick, upward-pointing tails which tapered towards the end. They had thick, stumpy legs and small spines on their backs. The Acristavus did not have any crest or spines on its head like other hadrosaurs, earning it the name 'non-crested grandfather.'

How many bones did an Acristavus have?

Though the exact number of bones this non-crested dinosaur species had has not been determined, skull and cranial skeletal fossils of this dinosaur have been unearthed, along with a number of partial vertebrae and limbs. The number of bones possessed by the average dinosaur has been worked out to be around 200; hence the Acristavus dinosaur most probably had around 200 bones.

How did they communicate?

Dinosaurs are known for their loud, earth-shaking roars, which is mostly how this dinosaur communicated. They mostly used bellowing roars, grunts of low rumbling noises to communicate in order to mate or chase away other dinosaurs from their territories. Visual displays were also probably used, with raising of the front legs, stomping, and tail whipping involved.

How big was an Acristavus?

The Acristavus could grow up to 20 ft (6.1 m) in length, making it a medium-sized dinosaur.

How fast could an Acristavus move?

Though the exact speed of this dinosaur is unknown, hadrosaurids were known to be quadrupedal in nature. It mostly moved fastest while hopping, reaching speeds of 55.8 ft (17 m) per second. While running, they could reach speeds of 49.2 ft (15 m) per second, meaning that they were quite fast despite their bulky bodies.

How much did an Acristavus weigh?

The Acristavus gagslarsoni has been estimated to grow up to 4000 lb (1814.4 kg) in weight.

What were the male and female names of the species?

A male dinosaur has been termed a saurus whereas the female dinosaur is known as saura. We do not make any distinction in sex while referring to dinosaurs, though.

What would you call a baby Acristavus?

Baby Acristavus dinosaurs were known as hatchlings.

What did they eat?

As Acristavus dinosaurs followed the diet of a herbivore dinosaur, they most likely sustained themselves on a diet of leaves, twigs, grass, roots, and rudimentary fruits, vegetables, and seeds.

How aggressive were they?

Though herbivorous dinosaurs did not prey on smaller creatures, they still had to be quite aggressive in order to protect themselves from the larger predatory dinosaurs such as various theropods and velociraptors. They had a number of defensive mechanisms, such as tough, scaly armor, bludgeon, and mace-like tails, and sharp horns and spikes, on their body in order to attack any incoming predators head-on.

Did you know...

The Parasaurolophus, another one of the hadrosaurids, was known for the elaborate ornamentation on its skull.

The Acristavus is closely related to other hadrosaurids- Brachylophosaurus and Maiasaura dinosaurs and belongs to the same clade- Brachylophosaurini. Like the Maiasaura dinosaurs, Acristavus is from the Cretaceous period as well.

The Acristavus skeleton remains found in the Two Medicine Formation of Utah consist of an almost complete skull, 11 cervical vertebrae, three incomplete dorsal vertebrae, several ribs, the left humerus, the left ulna, the right sternal, the left pubis, the left femur, the left tibia, two left metatarsals, five left pedal phalanges, and one right pedal phalanx.

The remains found in the Wahweap Formation of Utah consist of far fewer fossils, consisting only of a partial articulated skull, a complete braincase, and a cervical vertebra.

What is unique about Acristavus?

The Acristavus dinosaur did not have any ornamentation on its skull, which was expected from other hadrosaurids of that time. This has made it quite unique among hadrosaurs, with its name meaning 'non-crested grandfather' as well. It also gave rise to the scientific position that ancestor species of well-known hadrosaurs did not possess any skull ornamentation.

How has Acristavus' classification evolved?

The Acristavus dinosaur has been assigned to its own clade Brachylophosaurini, due to the lack of ornamentation on its head which makes it stand out from other hadrosaurs. This probably points to it being more primitive than its known relatives, which all had various cranial and snout ornamentation.

Here at Kidadl, we have carefully created lots of interesting family-friendly dinosaur facts for everyone to discover! Learn more about some other creatures from our Thecodontosaurus facts, or Wuerhosaurus facts for kids.

You can even occupy yourself at home by coloring in one of our free printable Acristavus coloring pages.

Main image by Nobu Tamura.

Second image by IJReid.

*We've been unable to source an image of Acristavus and have used an image of Brachylophosaurus instead. If you are able to provide us with a royalty-free image of Acristavus, we would be happy to credit you. Please contact us at [email protected].