Iguanodon Dinosaur Habitat- Cool Facts About Spike Thumbed Dinos


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The Iguanodon story becomes more relatable and even more interesting if we take a look at the dinosaur through the lens of the habitat it was living in during the Jurassic and Cretaceous periods of the Mesozoic era.

The Iguanodon was the second dinosaur formally named after multiple fossil bones had been found of the dinosaur. Iguanodon became known as a genus, and many dinosaurs were grouped under the name Iguanodon, although currently, there are only two valid species recognized as Iguanodons. Many people in the scientific community and also the general public know this dinosaur because of its signature spiked thumb.

Since then, its fossils have been found in many countries, and as often happens with the story of dinosaurs, as scientific techniques advance and more dinosaur fossils are found, the story needs to evolve.

Considering the Iguanodon dinosaur habitat, we can start to piece together the puzzle of its behavior, social behavior, nesting practices, what dinosaurs hunted them, and even how they might have protected themselves from predators.

So, what was the Iguanodon dinosaur habitat like? Their habitat was mainly forests, swamplands, coastal inlets, and islands. They lived in what is now present-day Europe and existed in the mid-Jurassic up until the late Cretaceous. Iguanodons were herbivores, and some paleontologists believe that they lived in herds and nested together, similar to the duck billed hadrosaurs. Iguanodon fossils have been found mainly in Europe, in the UK, Belgium, Germany, Spain, and Portugal.

There’s a lot to learn about Iguanodons. It’s interesting to note that Iguanodons have been reclassified several times as new fossils have shed new light on what these dinosaurs were like. Exploring the different habitats that these dinosaurs lived in tell scientists how they lived and what dinosaurs might have been hunting them and how they protected themselves from predators.

The two valid Iguanodon species, one named Mantellisaurus atherfieldensis and the other Iguanodon bernissartensis, will be the focus of this article. However, in the classification part, I will give an overview of Iguanodontidae. 

When I was a youngster, the Iguanodon was my favorite dinosaur, and I tried to learn as much about them as possible. Unfortunately, at the time, there were few books about dinosaurs in the library and, of course, no Internet. So I only had a handful of books and encyclopedias that had information about this type of dinosaur. It’s a pleasure to write about the Iguanodon now and share a snapshot of what we have learned about this dinosaur from the fossils and their habitat. Read on to find out more about the Iguanodon dinosaur habitat and the dinosaurs named Iguanodon.

I’ve researched information to write this article from many sources – multiple internet sites and magazines. However, some of the best reference knowledge is from books. If you are interested in checking out the best dinosaur books for adults on Amazon, you can find them by clicking here: Best Dinosaur Books for Adults

Where Did Iguanodon Dinosaurs Live? Iguanodon Predators – What Were They?

Iguanodons lived during the mid-Jurassic period up until the late Cretaceous. That stretches some 50-80 million years that this dinosaur existed. The earth was different in the mid-Jurassic and Cretaceous periods, especially in what is now modern-day Europe. It had multiple islands and coastal regions, and the temperature being much hotter than it currently is today. A dinosaur’s habitat will tell us a lot about the food it ate, other types of dinosaurs that it may have lived with or ran into, and the dinosaurs that hunted it. Let’s take a look. (Source)

Where Did Iguanodon Dinosaurs Live?

Iguanodon fossils have been found in the following places, which indicates what type of habitat the dinosaur lived in:

UK – England at Tilgate Forest and the Isle of Wight
Belgium – Bernissart coal mines
France
Spain
Portugal
Possibly other places in Europe, but only partial bones or skulls found and not enough to confirm if they were Iguanodon species
North America – some distant cousins to Iguanodon may have been found in North America (Utah, Montana) – dropped from being Iguanodon species
Asia – distant cousins may have been found. Currently, only partial fossils exist – dropped from being Iguanodon species.

YouTube Video About Iguanodon History

YouTube Video by “Past Time” which does an excellent recap of the history of Iguanodon fossils and is well media footage of actual fossils

It’s worth mentioning that the first Iguanodon fossils were found in England at Tilgate Forest by Mary Anne Mantell (the first Iguanodon teeth) and later her husband, Gideon Mantell. He was amazed by the Iguanodon teeth and decided to create an excavation team to search for other dinosaur remains. This discovery in 1822 led to the Iguanodon to be historically named the second dinosaur (the first was Megalosaurus). 

In 1878, 35 Iguanodon fossils were found in Brussels’ coal mine. This discovery led to much more understanding of the dinosaurs. It was also the first time when an almost full fossilized skeleton of the Iguanodon was found. Because so many of the dinosaurs’ species were found in the same place, besides adding knowledge to how the dinosaurs looked when the skeletons were reconstructed, there were also indications about the habitat. Some scientists think that it indicates a herd social behavior.

Lastly, in recent years there have been discoveries of Iguanodon fossils in the Isle of Wight. These fossils are significant because it adds to the knowledge we have of this type of dinosaur in England. They also give further insight into the habitat.

Iguanodon Dinosaur Habitats and What It Tells Scientists

The Iguanodon dinosaur habitat, from data gathered by geographic projections of prehistoric Jurassic Europe and Cretaceous Europe, varied because the geography covered a period from mid-Jurassic to late Cretaceous. 

The earth was hotter, and there were many islands and only a few landmasses. It had a subtropical atmosphere with swamps, riverways, coastal inlets, and vegetation to match. If you are interested to learn about different dinosaur habitats around the world, check out my article on this website: What Are the Different Dinosaur Habitats? 9 Places Where They Lived.

The type of habitats for Europe in the Jurassic and Cretaceous were:

● Water landscapes
● Lagoons and lakes
● Marshes
Swamps
● Coastal areas
Islands
● Woodland forests

In the Jurassic period, Europe looks different. It was a collection of islands and coastal areas linked from one island to another, and much of southern Europe was underwater. Later in the Cretaceous period, some of the islands grew into bigger landmass areas.

The temperature of the earth and the European areas during the Jurassic and Cretaceous was much hotter. As there was so much water in the island areas, it is also likely humid and subtropical. 

The vegetation during the Jurassic period consisted of conifers, palm trees, and ferns. During the Cretaceous, there would probably be deciduous trees and new plants that flower and blossom.

We now start to get a snapshot of the types of habitats the Iguanodon might have lived in. The Iguanodon was likely used to being around water. Although paleontologists don’t think it was a swimming dinosaur, it would spend most of its time on land.

Predators That Hunted Iguanodons

Plant eating dinosaurs were always at risk of being attacked by a predator. The Iguanodon dinosaur habitat discussed above gives a glimpse of what the landscape looks like for these dinosaurs. It had swamps and waterways as well as coastal vegetation. 

One way for dinosaurs to avoid being hunted and eaten by predators was to hide in the vegetation; in this case, there would be swamp vegetation, conifer forests, and coastal in ways where Iguanodons could hide during the Jurassic in Europe. During the Cretaceous, there would most likely be more vegetation and wooded forests. But what kind of predators were they up against?

Torvosaurus gurneyi – this dinosaur has been identified as the largest predator in Europe during the late Jurassic period. A distant cousin to the T. Rex, it was slightly smaller than the North American T Rex. This dinosaur would likely have hunted Iguanodons. (Source) https://www.nbcnews.com/science/science-news/newly-named-dinosaur-was-europes-largest-jurassic-predator-n45196

Razanandrongobe sakalavae – this dinosaur’s fossils were found in Madagascar, and paleontologists estimate that the predator’s length reached 23 feet and weighed approximately 2200 pounds. The habitat in Jurassic Madagascar was a coastal or island habitat. Although there have not been any Iguanodon fossils found, there’s a good chance that the Razanandrongobe hunted it. It lived during the mid-Jurassic. (Source) https://www.wptv.com/news/science-tech/the-top-jurassic-predator-was-a-giant-crocodile-called-razanandrongobe-sakalavae

Baryonyx walkeri – this dinosaur was closely related to the Spinosaur, except it lived in the Cretaceous period of England. The best fossil skeleton of this dinosaur, one of the most complete theropod dinosaur skeletons found in the UK, had a large claw on its first finger, and it refers to the meaning of its name: “heavy claw.” 

Found in 1983, other fossils were found in Spain and Portugal (Iberia) and other parts of the UK. We know from the Spinosaurus aegyptiacus that paleontologists suggest that these types of dinosaurs were agile swimmers and spent much of their time in the water. That matches with Jurassic Europe’s habitat and the habitat that Iguanodon lived in.

Neovenator salerii – A predator dinosaur, its fossils have been found on the Isle of Wight and lived during the Early Cretaceous. Interestingly, at the site where its fossils were found, there were also fossils of Iguanodon. It is related to Allosaurids, and its skull outlines how effective a predator it must have been. The dinosaur’s snout had five teeth and full rows of teeth, and its nostrils were large and long. Other Neovenator salerii fossils have been found in France. (Source) https://en.m.wikipedia.org/wiki/Neovenator

Megalosaurus buckendii– The first dinosaur that was formally named, was found in England in 1822. This dinosaur lived during the mid-Jurassic period and most likely hunted Iguanodon, especially as fossils were found in the same country. It is a sister species of Torvosaurus. Several other Megalosaurus buckendii fossils were found in the UK and France, although never a complete fossils skeleton. 

What Type of Dinosaur Is an Iguanodon?

The Iguanodon is a theropod dinosaur that most likely stood on its hind legs and possibly used its forearms, the standing on all four limbs. It is closely related to the Hadrosaurs, the duck billed dinosaurs and was also a herbivore. Examining a bit of the Iguanodon anatomy will give us a glimpse into the Iguanodon dinosaur habitat. We can understand a little bit better how these dinosaurs lived.

The Iguanodon’s teeth were also similar to duckbilled dinosaurs in that they were slightly conical and flat, shape so that they could grind vegetation. The most striking feature of the iguana done was its spiked thumbs, which was on each forearm. The exact usage of these spiked thumbs is still not known. However, many paleontologists believe that it was used for defense against predators or stripping vegetation.

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Related Dinosaur Articles You Might Also Be Interested In:
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In this section, I’ll go over how the Iguanodon classification has evolved, show the current clades and classification that Iguanodon belongs to, and finally show an Iguanodon species table.

Iguanodon Classification and The Different Types of Iguanodons

As mentioned above, there are actually only two species of Iguanodons that are currently excepted as valid Iguanodon species.

The first is Mantellisaurus atherfieldensis, named after the people who discovered the first teeth and fossil skeletons in England, Gideon, and Mary Anne Mantelli. The second is the Iguanodon bertissartensis, the Belgian fossils found by Jules Créteur and Alphonse Blanchard in a coal mine.

Iguanodon was the first genus of dinosaurs to be named, and over 150 years, multiple dinosaurs were grouped under this common name. As more and more fossils similar to Iguanodons were discovered, it became even more complex and even confusing when the genus split and reclassified.

Recently, there were fossils of the Mantellisaurus found on the Isle of Wight, which included not only fossil skeletons but also footprints. 

In the figures below, I show a simplified cladogram (from 2017) of Iguanodontidae and Ankylopollexia, including the two valid Iguanodon species. (Source)

Table of Iguanodontidae

Below is a table of dinosaur species closely related to the Iguanodons as per 2017 cladogram of Ankylopollexia. In the first column, I name the dinosaur species, then in the second column, I describe any significant features of the dinosaur, and then finally, I list where their fossils have been found. 

***Table of Iguanodons Listed Dinosaur Description Where Fossil Found        

What Did an Iguanodon Eat? Plus Facts About Its Spiked Thumbs and Social Behavior

When Mary Ann and Gideon Mantell found the fossilized teeth of the first Iguanodon, they noticed the similarity of the teeth to modern-day iguanas. They decided to name the dinosaur after iguanas. The difference between the Iguanodon dinosaur teeth to present-day iguanas is that they are packed closer together. 

When Mary Ann and Gideon Mantell found the fossilized teeth of the first Iguanodon, they noticed the similarity of the teeth to modern-day iguanas. They decided to name the dinosaur after iguanas. The difference between the Iguanodon dinosaur teeth to present-day iguanas is that they are packed closer together.

Iguanodon Teeth and What Did and Iguanodon Eat?

The Iguanodon dinosaur habitat was different in the Jurassic compared to the Cretaceous. In the Jurassic period, the vegetation consisted of:

Ferns – both tree ferns and smaller species
Ginkgo
Cycads – ancient and original palm trees
Pine trees
Redwoods
Cypress
Yews

In the Cretaceous, deciduous trees (trees with leaves) begin to appear and thrive and even become dominant. There were also flowering trees and bushes. These were:

Willow
Birch
Oak
Maple
Laurel
Elm
Sequoias
Grass
Flowering bushes and shrubs

It’s important to keep in mind that Iguanodon lived in what is now modern-day Europe. It was more subtropical and a type of island and coastal type habitat and vegetation during the Jurassic and Cretaceous. (Source) It means that in the big picture during the Jurassic, you have ferns and conifers and cycads that lived in those islands and coastal areas. (Source)  During the Cretaceous, those deciduous trees and grass and flowering bushes exist in the same island and coastal area, and it is these types of plants that an Iguanodon would eat.

The Iguanodon’s Spiked Thumbs

The most recognizable physical characteristic of Iguanodons was their thumb spike on each of their forelimbs. The spike was on its fifth finger and stuck out. The size of the thumb spike was as long as the other digits, and the shape was conelike. Interestingly, when the first fossils were found in England, the spike was put on the dinosaur’s forehead. Later, when the Belgian fossils were found, which were complete, it was clearly seen that the spike was on each of the forelimbs and fused at the wrist.

The exact use of the spiked thumb is not known. Paleontologists suggest that it could be used as a defense against predators. Scientists even studied if the thumb possibly had poison, but no poison glands were found. Suppose we think about the types of predators hunting Iguanodons from the list descriptions above. In that case, it is hard to believe that the spiked thumbs would be sufficiently effective in defending itself. 

Another use that scientists think it could be used for is slashing vegetation. Hard branches or tough palm tree branches could be cut with a spiked thumb like that. 

Iguanodon Social Behavior, Nesting and Eggs

Once we have a snapshot of the Iguanodon dinosaur habitat, we can start to connect to what the social behavior and nesting habits were of this dinosaur.

We can only speculate about the social behavior of the Iguanodon. We can still make some correlations to Hadrosaurs as paleontologists have classified them as similar and most likely had similar behavior. Scientists believe that Iguanodons grouped themselves in herds. 

They did this for a few reasons because a herd can provide extra protection from predators, especially as predators hunted them. It becomes useful when they are eating vegetation, which may be noisy, and they cannot hear predators creeping upon them. In a herd, the ones that are not eating can keep watching whether predators are coming to close.

Another interesting social behavior is nesting habits. Although paleontologists have not found multiple nesting and egg sites of Iguanodons, nesting sites of Hadrosaurs in North America (Montana, USA) have indicated that herds of Hadrosaurs nested together. Check out my article on duckbilled dinosaurs on this website here.

Perhaps the most significant fossil site of Iguanodons was the Belgian fossil find in 1878. In a coal mine, they found 35 fossilized skeletons of Iguanodons. This discovery indicates that these dinosaurs could very well be living as a group in herds. (Source)

Final Thoughts

There are about 50 dinosaur fossil discoveries on average every year, many of them new dinosaurs. As discussed, the Iguanodon is one of the dinosaurs that is starting to be found on many continents, and they lived in various habitats.

As exciting as finding new fossils is, it can also mean that new knowledge about older dinosaur fossils needs to be reevaluated and leads to new classifications and descriptions, as with Iguanodon’s case becoming Mantellisaurus. 

Because Iguanodons lived during the Jurassic, some of the fossils are older and give us an insight into how dinosaur habitats evolved for those dinosaurs that lived through multiple Mesozoic periods. Who knows what new fossil discoveries will tell us about Iguanodontids in the coming years.

After many years since my childhood has passed, it’s interesting to know that Iguanodons are an important dinosaur in the scientific community. It was not just a passing fancy from my youth. Here’s to the spiked thumb dinosaur- thumbs up!

Lastly, if you or someone you know loves dinosaur toys, then check out my favorite dinosaur toy gifts on Amazon: Best Dinosaur Toys – Remote Control

Michael Haralson

I'm the owner of Adventure Dinosaurs website. Although I have an extensive business background, I am fascinated with dinosaurs and have been since childhood. I'm fortunate enough to have visited fossil museums in Europe (UK, Germany, and Spain), the US (California, Texas) and in Asia (China). Currently, I'm location independent with a home base in Kirkkonummi, Finland.

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