An Ultimate Guide to Maiasaura: The Good Mother Lizard

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Name MeaningGood MotherHeight2.4 meters (8.2 ft.)
PronunciationMy-ah-sore-ahLength9 meters (30 ft.)
EraMesozoicLate CretaceousWeight3,000 to 4,000 kgs. (6,600 to 8,800 lbs.)
ClassificationDinosauria, Ornithischia, & OrnithopodaLocationNorth America (United States)

Maiasaura Pictures

Computer generated image of Maiasaura
Computer generated image of Maiasaura | Cyrannian via Jurassic World Evolution Wiki

The Maiasaura

Gage Beasley Prehistoric's Maiasaura Concept
Gage Beasley Prehistoric’s Maiasaura Concept

The Maiasaura is a species of Hadrosaurid that lived in North America during the Late Cretaceous period around 99.6 to 66 million years ago.

Like other duck-billed dinosaurs the Maiasaura was a herbivore, with a mouth designed for eating in bulk. 

The first remains of the Maiasaura was discovered in 1978, and it was only a year later this genus was described.

The name Maiasaura translates to “good mother” and this dinosaur was given this name since when it was found it was caring for a nest of its eggs.

This article will go over everything that has been learned about the Maiasaura from the hundreds of bones that have been uncovered. 

Since these dinosaurs were herbivores they did not prey on other dinosaurs, but they still played an important role in their prehistoric environment. 

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Physical Characteristics

Gage Beasley Prehistoric's Maiasaura Size Comparison Chart
Gage Beasley Prehistoric’s Maiasaura Size Comparison Chart

Maiasaura were very large animals that grew up to 9 meters (30 ft.) long, and had a body mass estimated up to 4 metric tons (4.4 tons) when fully grown. 

Like other hadrosaurids, Maiasaura had beaked faces, with very thick noses. 

The duck-billed faces of these dinosaurs were accompanied by powerful jaws, and many teeth which help them feed on various vegetation. 

In front of their eyes this dinosaur had a small crest that was spiked, and resembled two very small horns.

It is still unknown what the crest of this dinosaur was used for, but it is possible they could have used them for headbutting each other for dominance. 

Maiasaura was quadrupedal, but had the ability to walk on both four, or two legs. 

Maiasaura had the ability to walk on all fours or just on two legs
Maiasaura had the ability to walk on all fours or just on two legs | LEONELLO CALVETTI via GettyImages

The back legs of these dinosaurs were more heavily built when compared with their front legs, and were helpful for running.

Maiasaura also had a long tail that was pointed, and their bodies were very bulky.

This dinosaur had a height estimated at around 2.4 meters (8.2 ft.), but they would have been even larger when standing on two legs. 

When compared with other hadrosaurids, the Maiasaura was one of the largest species, but was smaller and less bulky than dinosaurs like Edmontosaurus

Habitat and Distribution

Maiasaura lived in North America during the Late Cretaceous period around 76.7 million years ago, and fossils from this species have been found in what is now Montana, and Alberta Canada.

North America during the Cretaceous period was very different than it is today, and Montana where the Maiasaura was discovered would reside in prehistoric northern Laramidia.

In the Cretaceous period North America was split in two by a large waterway called the Western Interior Seaway, and the land overall was filled with lots of rivers, and swamps.

The two land masses Laramidia, and Appalachia in North America would eventually be connected, but only after the extinction of the Maiasaura

Woodlands, coastal plains, and swamps are the environments that Maiasuara lived in.

Plants like conifers, cycads, ginkgos, ferns, and angiosperms were present in the Maiasuara’s environment. 

Laramidia’s fossils are much more abundant than in Appalachia, and their abundance is what helped paleontologists learn more about the animals in North America as a whole in the cretaceous environment. 

Fossil skeleton of Maiasaura at the Field Museum of Natural History
Fossil skeleton of Maiasaura at the Field Museum of Natural History | Zissoudisctrucker via Wikimedia CC BY-SA 4.0

Maiasaura’s  fossils were limited to a specific region,and they and had a much smaller range when compared with other hadrosaurids in North America. 

Behavior and Diet

Maiasaura, like other duck-billed dinosaurs, were strictly herbivores that fed on the variety of plant material that was in their environment. 

A coprolite discovery of the Maiasaura is how the diet of these dinosaurs has been examined, and a study done in 2007 helped bring more insight into what these animals ate. 

Angiosperms, branches, leaves, rotting wood, grass, and tree bark are some of the things that Maiasaura would have eaten.

 It is possible that this dinosaur was a browser and grazer.

A Maiasaura within a forest during the late cretaceous
A Maiasaura within a forest during the late cretaceous | EatThatPie via The Isle Wiki

Standing on their hind legs also would have helped the Maiasaura reach vegetation higher in trees they would have not been able to get on all fours. 

The poop found of the Maiasaura also suggested they ate rotting wood regularly. 

While eating wood is not typically common in larger herbivores, the amount of wood inside the coprolites, and the absences of smaller fragments of wood like twigs suggest that the Maiasaura ate wood on purpose.

The patterns of tissue damage in the fecal wood show what they ate had lots of fungal degradation, but along with the rotting wood Hadrosaurid poop has also been discovered with crab shells in it.

Paleontologists believe that dinosaurs like Maiasaura ate rotting wood, and shells to supplement what was lacking in their diet from the grasses and flowering plants. 

Wood in this dinosaur’s diet would have also helped in periods of drought, and when there was little plant life.

The Maiasaura had more than 900 short teeth, and their duck-billed mouths helped them bite through thick vegetation.

Lots of teeth allowed the Maiasaura to chew through lots of plants, and if they ever lost their teeth they had the ability to regrow them back. 

Maiasaura skull with rows of teeth
Maiasaura skull with rows of teeth | Clumsystiggy via Prehistoric Wiki

The large mouths helped the Maiasaura eat in bulk, and it is estimated that these dinosaurs would eat up to 90 kgs (200 lbs.) of vegetation a day to support their large size.

Life Cycle

The Maiasaura’s name translates to the “good mother”, and they got their name since the holotype of this fossil was discovered caring for a nest of its eggs.

Statue of Maiasaura with hatchlings at a dinosaur park
Statue of Maiasaura with hatchlings at a dinosaur park | Disneysaurus via Dinosaur Wiki

Maiasaura not only lived in herds, but also nested in colonies, and like their name suggests, had a very good motherly instinct. 

The nests of the Maiasaura were made in the earth, and they laid around 30 to 40 eggs in a circular pattern on the ground.

The eggs of this dinosaur were very large, and are around the size of an ostrich egg.

When breeding Maiasaura laid their eggs together in communal nests much like seabirds of today, and their nests were placed about 7 meters (23 ft.) apart from each other. 

The heat from the ground, and things like rotting vegetation helped incubate the eggs, and when born the Hadrosaurids were not fully capable of walking. 

Fossils from these hatchlings showed they had hard worn teeth, and the mothers would bring vegetation for their young to feed on.

When born young Maiasaura grew to be around 41 to 147 cm (16 to 58 in.) within their first year of life, and they would care for their young in their nest until they could leave the nest.

Young Maiasaura had larger eyes, and a shorter snout, and fossils suggest juveniles spent their life on two legs, before switching to become more quadrupedal as adults. 

Reconstructed cast of a Maiasaura emerging from its egg
Reconstructed cast of a Maiasaura emerging from its egg | tracy the astonishing via Wikipedia CC BY-SA 2.0

During the first year of life the Maiasaura had a mortality rate of around 89.9 %, and once they got to their second year this would drop drastically to 12.7%.

It took around 8 years for the Maiasaura to reach sexual maturity, and the older they got the more likely it was for this dinosaur to die.

Evolution and History

The Maiasaura was discovered in 1978, when the first specimen was uncovered in Bynum Montana, by resident Laurie Trexler. 

The type species Maiasaura peeblesorum is the only named species of this dinosaur.

Maiasaura was discovered alongside juveniles, and eggs, and the location where they were found was named Egg Mountain.

Fossils of Maiasaura with hatchlings at the Wyoming Dinosaur Center
Fossils of Maiasaura with hatchlings at the Wyoming Dinosaur Center | Meghunter99 via Fossil Wiki

Related to other Hadrosuarids, the Maiasaura is a member of the Brachylophosaurini tribe.

Hadrosaurids like the Maiasaura are descendants of dinosaurs from the Jurassic period like Iguanodonts, which likely originated from North America before expanding into Asia. 

Interactions with Other Species

Maiasuara was a very common herbivore in North America during the late Cretaceous period. 

These dinosaurs were very abundant and were used as food for the various carnivores they lived with.

A Maiasaura being stalked by a predator
A Maiasaura being stalked by a predator | EatThatPie via The Isle Wiki

Other herbivores like ceratopsians, and ankylosaurids also lived with the Maiasaura.

Fossil beds where this dinosaur has been found have given insight into the types of species that coexisted with Maiasaura.

Dinosaurs that lived alongside Maiasaura include:

Since the Maiasaura did not have special defenses, these dinosaurs relied on safety in numbers, and lived in large groups that could have reached more than 1,000 members. 

Illustration of a herd of Maiasaura walking along a creekbed
Illustration of a herd of Maiasaura walking along a creekbed | Meghunter99 via Fossil Wiki

The groups of Maiasaura would have also included other herbivores, and living together in such large groups increased the survival of all of the dinosaurs. 

Maiasaura also could have kicked, and stomped to ward off predators, but they had the speed to escape most predators. 

Dinosaurs like Troodon and tyrannosaurids are the dinosaurs that preyed on Maiasaura the most.

Being so abundant they were a reliable food source, and had similar roles to animals like gazelles today. 

Cultural Significance

Maiasaura may be a simple looking dinosaur, but this species has been essential in learning more about Hadrosaurids, and dinosaurs overall.

There have been more than 200 specimens of Maiasaura discovered, which include several different growth stages of this dinosaur. 

The amount of stages found from this dinosaur have allowed in-depth studies not possible with other species.

Baby Maiasaura skeleton from the Royal Ontario Museum
Baby Maiasaura skeleton from the Royal Ontario Museum | Meghunter99 via Fossil Wiki

The growth rate, and life cycle of the Maiasaura is one of the most well known amongst all dinosaurs. 

Maiasaura fossils have been mounted and showcased, and they are one of the most complete fossil specimens in the world. 

This dinosaur was one of the first examples of eggs fossilized, and dinosaurs feeding their young. 

These dinosaurs have also been showcased in several games like Jurassic Park, and the many fossils found of this dinosaur have made their depictions to be more accurate than other dinosaurs.

Maiasaura as seen in Jurassic World Evolution
Maiasaura as seen in Jurassic World Evolution | Steamblust via Jurassic World Evolution Wiki


Maiasaura is one of the several known Hadrosaurids, and this genus was one of the many types of herbivorous dinosaurs that lived in North America during the Cretaceous period. 

Unlike other herbivores which had extreme size, or defenses like large horns, the Maiasaura had no noticeable defenses, but managed to thrive alongside some of earth’s most dangerous predators. 

The abundance and completeness of Maiasaura fossils that have been discovered have allowed paleontologists to better study Hadorsaurids, and gain a better understanding of dinosaurs overall. 

These dinosaurs were very abundant in their range, and managed to dominate their environment not with strength, but numbers. 

While there is still lots to learn about dinosaurs, genus like the Maiasaura have furthered our understanding of animals from the Cretaceous period in North America. 


How fast could the Maiasaurua run?

While Maiasaura was faster than most larger dinosaurs, it was the smaller, quicker carnivores they had to worry about the most. 

The Maiasaura is estimated to have a max speed at around 45 kilometers per hour (28 mph.), and their speed is one of the ways that help protect them from predators.

What type of skin did the Maiasaura have?

The Maiasaura is a type of Hadrosaurid, and fossils from these dinosaurs showed they had scaly skin, and did not have feathers unlike other dinosaurs that lived alongside them at the time.

How did the Maiasaura go extinct?

It is believed that the Maiasaura went extinct when the Chicxulub asteroid hit North America, changing the earth’s climate, and killing all of the non-avian dinosaurs, and around 75% of species in the world. 


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