Fun Siamosaurus Facts For Kids

Sharon Judith
Oct 20, 2022 By Sharon Judith
Originally Published on Sep 27, 2021
Edited by Monisha Kochhar
Fact-checked by Sakshi Raturi
The Siamosaurus dinosaur is known only from its tooth fossil. Read on to discover more fun and interesting Sianosaurus facts!
Age: 3-18
Read time: 6.2 Min

Siamosaurus was a carnivorous dinosaur that was found to have inhabited parts of Asia. The Siamosaurus fossil has been found in places like Thailand and few parts of Japan. They were believed to have roamed the earth during the Early Cretaceous period about 129.4-125 million years ago with their teeth fossils being found in the Roi Et Province (Thailand), Chaiyaphum Province (Thailand), and Nagano Prefecture (Japan). Since only part of the Siamosaurus skeleton structure is found in the teeth, very little is known about their characteristics and behavior. The teeth of the Siamosaurus were straight and had some lines on them in length. The wrinkled enamel of the teeth made it similar to that of Baryonyx, a related genus. Scientists and paleontologists are still doubtful of the Siamosaurus dinosaur, saying that its teeth made it hard to differentiate them from other early cretaceous spinosaurids. Some say that it's not a dinosaur at all! According to the authors, this dramatic size range suggests the teeth are from individuals of different ages. In 1983, French paleontologist Eric Buffetaut and his associate Rucha Ingavat described the Siamosaurus fossil remains as being specimens that were related to an unusual theropod dinosaur or to some unknown crocodilian. In 1986, a re-examination of the fossil by the same authors placed their range in a new genus and species of spinosaurid theropod, which they named Siamosaurus suteethorni. From studying the discovered fossil teeth in-depth, it was concluded that they were piscivores and probably ate fish and other sea animals. Furthermore, in 2010, Roman Amiot and his colleagues, through research, found out that the oxygen atomic ratios in spinosaurid remains suggest that these dinosaurs must have definitely had semiaquatic lifestyles. They compared the teeth of various spinosaurids like Baryonyx, Siamosaurus, Spinosaurus, and Irritator to other carnivorous dinosaurs and concluded that most spinosaurids were semiaquatic. This meant that this spinosaurus dinosaur spent a part of its life either in water or on land. Some paleontologists believe that these dinosaurs had their range in parts of Asia too.

If you'd like to learn more about other similar dinosaur species, check out our Incisivosaurus fun facts for kids or Puertasaurus interesting facts that you're sure to enjoy!

Siamosaurus Interesting Facts

How do you pronounce 'Siamosaurus'?

The name of this unusual theropod dinosaur from the early cretaceous of Thailand is pronounced as 'Sy-am-o-sore-us'.

What type of dinosaur was a Siamosaurus?

The Siamosaurus dinosaur was a theropod that was believed to have an aquatic lifestyle which meant that they lived partly on water and partly on land.

In which geological period did Siamosaurus roam the earth?

These dinosaurs, who were piscivores like all other spinosaurids, roamed the earth during the early cretaceous period in Thailand and certain parts of Japan but that is yet to be proven.

When did Siamosaurus become extinct?

Siamosaurus became extinct about 129-125 million years ago! These large carnivores that were found in Asia like Thailand and parts of Japan have only been studied from fossil teeth, which is the only part of the skeleton discovered so far.

Where did Siamosaurus live?

These dinosaur species were semi-aquatic. This means that most of its life was spent on both land and water, partly. They made their homes in wetlands, meandering rivers, and semi-arid floodplains.

What was the Siamosaurus' habitat?

This means they used to live in similar habitats like those of crocodiles, hippopotamuses, and turtles. It also means they existed at the same time and place as some other large predators without competing for food.

Who did Siamosaurus live with?

Whether the Siamosaurus lived in groups or alone is not known in detail but since they are theropods, they would have lived in herds and moved from habitat to habitat feeding on carcasses. It coexisted with other theropods, sauropod, and iguanodontian dinosaurs. Its possible role as a piscivorous predator might have reduced the prominence of long-snouted crocodilians living in the same time and place.

How long did a Siamosaurus live?

The number of years that these dinosaurs lived is unknown due to the lack of remains. Nonetheless, like all dinosaurs, they would have lived for a very long time!

How did they reproduce?

With only the teeth fossil available for scientists to study these dinosaur species, the reproduction patterns among them were difficult to learn. The reproduction would have been oviparous with the female dinosaur laying eggs in clutches and incubating them for a brief period.

Siamosaurus Fun Facts

What did Siamosaurus look like?

This dinosaur, which comes from the genus of theropods, lived during the early cretaceous period in Thailand. Various paleontologists have tried to portray how this dinosaur would have looked through research and studies but they have struggled in doing so because the only part of the skeleton obtained was the teeth. The exact size of the Siamosaurus is not known in-depth but it was estimated to be about 562 lb (255 kg) and about 30 ft (9.1 m) in length. Attempts are still being made to understand the characteristics and features of this dinosaur. The semiaquatic adaptations might suggest that Siamosaurus was able to live alongside other theropods without competing for food since they lived in different habitats and possessed different diets and ecological niches.

The tooth fossil of this dinosaur had lines on it and had a wrinkled enamel.

How many bones did a Siamosaurus have?

The Siamosaurus bones have been located only in fragments so very little information exists on the number of bones they had. However, the Siamosaurus size is massive and hence, these dinosaurs would have had over 100 bones!

How did they communicate?

Being dinosaurs, making loud growls, and using body language. Some other ways could have been using elements of the environment around them like water and trees!

How big was the Siamosaurus?

The Siamosaurus dinosaur that had a semiaquatic life was about 4.8 ft (1.46 m) in height and 30 ft (9.1 m) in length. The height of this dinosaur was the same as a kangaroo!

How fast could a Siamosaurus move?

Very little is known about the speed at which the Siamosaurus moved. Its short limbs and stout but large body would have contributed to it probably being slow in movement.

How much did a Siamosaurus weigh?

The Siamosaurus dinosaur weighed about 562 lb (255 kg), the same as a polar bear!

What were the male and female names of the species?

There are no specific male or female names for this species. They are known by their common name which is Siamosaurus or scientifically, Siamosaurus suteethorni.

What would you call a baby Siamosaurus?

A baby Siamosaurus suteethorni dinosaur is called a hatchling or a nestling, just like all other baby dinosaurs.

What did they eat?

This spinosaurid dinosaur consumed small fishes and amphibians for food. Being piscivores and living partly in the water, this spinosaurid would have probably consumed mackerel, anchovies, herrings, and so on.

How aggressive were they?

As they come from the same spinosaurid family, the Siamosaurus suteethorni would have been quite dangerous and aggressive since they are territorial animals and get defensive when another animal enters its domain or habitat.

Did you know...

Even though these dinosaurs had four legs, there is speculation that these dinosaurs would have crouched and walked. It is also the first spinosaurid dinosaur to have been first identified in Asia!

Why are they called Siamosaurus?

They are called Siamosarus because these species resemble a Siamese lizard. The scientific name of this spinosaurid, Siamosaurus suteethorni was given in honor of the Thai paleontologist Varavudh Suteethorn and was formally described back in 1986.

How strong were Siamosaurus teeth?

The characteristics and features of this animal's teeth are not known in detail but given their appearance, these dinosaurs are believed to have really strong teeth, making it easier to tear into meat and fish carcasses!

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 Ichthyovenator facts, or Volgatitan facts for kids.

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


Main image by FunkMonk (Michael B. H.).

Second image by TIDTAMTOR.

Siamosaurus Facts

What Did They Prey On?

Fish and small amphibians

what Type of Animal were they?


Average Litter Size?

1-2 eggs

What Did They Look Like?


How Much Did They Weigh?

562 lb (255 kg)

Skin Type


How Long Were They?

30 ft ( 9.1 m)

How Tall Were They?

4.8 ft (1.46 m)









Scientific Name

Siamosaurus suteethorni

What Were Their Main Threats?

Natural disasters

What Habitat Did They Live In?

Meandering rivers and semi-arid floodplains

Where Did They Live?

Thailand and Japan
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Written by Sharon Judith

Bachelor of Arts specializing in Psychology, Economics, and Sociology

Sharon Judith picture

Sharon JudithBachelor of Arts specializing in Psychology, Economics, and Sociology

A humanities and Science student, Sharon holds a Bachelor of Arts degree with a specialization in Psychology, Economics, and Sociology from Mount Carmel College and is currently pursuing her Master's in Science from Bournemouth University. She is passionate about research, content writing, and development, and has a keen interest in international finance and economics. With her strong analytical skills and inquisitive mind, she is always striving to deepen her knowledge and understanding of these subjects.

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