What Dinosaurs Ate Fish? The Surprising Fish Hunting Dinosaurs

Knowing what an animal eats helps us understand more about it. In dinosaurs’ case, paleontologists have determined that there were meat-eating dinosaurs – the carnivores and the plant-eating dinosaurs – the herbivores. There are two lesser-known groups of dinosaurs also. The omnivores are the dinosaurs that ate both meat and plants. Often they were opportunistic eaters, eating plants when they were hungry but could not find a lizard to eat. The last group hunted and ate fish as its main diet choice.

What Dinosaurs Ate Fish?

So, what dinosaurs ate fish? Dinosaurs that eat fish are called piscivores or piscivorous, from the Greek (root word fish) and means “fish-eating.” Based on fossilized stomach contents (fish skeletons or scales), Spinosaurus, Baryonyx, Suchomimus, and Liaoningosaurus were dinosaurs that ate fish. Paleontologists also suggest that these dinosaurs hunted and ate fish because their anatomy – snout, teeth, and arms- are adapted to catch fish.

These dinosaurs lived in a river delta or coastal habitats, and recently a few of them have been confirmed to have been powerful swimmers. Modern-day piscivorous animals include reptiles, birds, and mammals.

In the Mesozoic Era, various dinosaurs, such as herbivorous, carnivorous, and predatory types, thrived. Notably, Spinosaurus and Baryonyx, both carnivorous types, showcased a preference for eating fish as evidenced by fossil records.

Even the predatory Carnosaurs occasionally consumed fish. Certain amphibious dinosaurs, owing to their partial aquatic habitation, were more inclined towards a piscivorous diet, underlining a complex marine food chain. The prominence of such divergence in dietary habits significantly pointed to the impact of evolution on these prehistoric animals during the Jurassic and Cretaceous periods. Investigations in the realm of paleontology have provided these fascinating revelations about the prehistoric era.

Although not dinosaurs, the aquatic Ichthyosaurs and Plesiosaurs, famous prehistoric marine reptiles, were hypercarnivores whose diets included a variety of marine life, with fish being a major part. Theropods, a category of dinosaurs that includes the Spinosaurus and the unique Baryonyx, were known to consume fish. The Spinosaurus, in particular, exhibited specific adaptations for a piscivorous diet, evident from its crocodile-like skull.

Similar evidence from the fossilized fish scales in Baryonyx’s gut area confirmed its piscivorous nature. These findings, derived from the Prehistoric Era, specifically the Jurassic and Cretaceous periods, offer an understanding of the varying dietary habits and ecological roles of these ancient creatures, thereby giving us a snapshot of life during the reign of the dinosaurs.

One question often confusing when it comes to piscivorous dinosaurs and animals is, what if the dinosaur eats meat and fish? I’ll use the Wikipedia description of a piscivorous animal in the context of this article and dinosaur descriptions, which roughly states that an animal is piscivorous if they “mainly” eat fish.

When it comes to dinosaurs, we will never know for certain, so I will use what paleontologists have suggested and look for clues in the dinosaur’s habitat, anatomy features, and possible swimming and hunting behavior.

It’s interesting to note that the piscivorous dinosaurs, Spinosaurus, Baryonyx, and Suchomimus were theropod dinosaurs that primarily walked on their hind legs. However, Liaoningosaurus was an ankylosaur, typically armored herbivore dinosaurs, and walked on all four limbs. More about all four of these dinosaurs will be covered later.

Modern-day reptile and bird piscivores can give some additional clues to how these fish-eating dinosaurs lived and what their habitat and behavior might have been like. Animals like crocodiles, alligators, a few snapping turtle species, and even birds will hunt fish. Some piscivores eat only fish. Others are a mix, like crocodiles and alligators. They are just as happy to eat meat if they can catch it. (Source)

The clues that modern-day animals can give about piscivores are related to their anatomy and their habitat. For instance, the crocodile snout is narrow. It can sense the movement of fish while swimming, and its teeth are for grasping and tearing. Likewise, the Spinosaurus had a similar shaped snout and teeth. 

It’s also important to take a look at the habitat of piscivorous dinosaurs, and I’ll cover this as well in the article. Read on to find out more!

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Adaptations for Fish-Eating Dinosaurs

This next section will examine the dinosaurs that paleontologists consider to be piscivorous based on key factors such as evidence collected on or in the fossil dinosaur skeleton, anatomy, surrounding habitat, and similarity to modern-day reptiles or birds. Although all the data may not be available for each dinosaur, I work to give a brief overview of the dinosaur and touch on its classification. Additionally, where relevant, I’ll take a look at the dinosaur’s swimming and hunting ability. In this section, the dinosaurs are considered to have a piscivorous diet primarily, although it’s impossible to tell whether meat or vegetation was also eaten.

In determining whether a dinosaur ate fish, one of the primary ways to determine it is to examine the fossil for stomach contents such as fossilized fish bones or fish scales. Of course, there is a possibility that the dinosaur was scavenged after death, and the fish might have died at that time, but nothing is always 100% certain after millions of years.

Adaptations that reveal itself from the dinosaur’s fossilized skeleton indirectly determine that the dinosaur was a piscivore. Adaptations such as a narrow snout and rows of sharp teeth make it easier for the dinosaur to snap and catch fish they might be hunting. 

Additionally, arms and claws that help capture fish from getting away once bitten are adaptations seen, for instance, in modern-day alligator gars.

When it comes to hunting larger fish or strong fish that would put up a fight when hunted, such as prehistoric sawfish, adaptations of the snout, teeth, arms, and claws would be useful in going after these larger fish.

The Spinosaurus – The Swimming Dinosaur That Ate Fish and Was Adapted to Water Environments

The Spinosaurus is considered one of the largest theropod dinosaurs, bigger than even the T. Rex. What makes this dinosaur unique based on discoveries (Source – insert NatGeo) and paleontology research, is that it is considered to have lived an aquatic life, spending more than 50% of its time in the water, making it the first water dinosaur. It lived during the Late Cretaceous. 

So it comes as no surprise that living in its river flats and delta habitat, it is considered a dinosaur that ate fish. Whether its diet was made up of only fish, a combination of fish and aquatic birds and turtles, or whether it was opportunistic and hunted hadrosaurs when the chance came, we will perhaps never know for certain. What is certain was that this dinosaur had some exceptional swimming and hunting adaptations that certainly makes it an apex predator.

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YouTube Video About the Fish-Eating Spinosaurus

Fossils of the Spinosaurus aegyptiacus – have first been found in Egypt in 1912, although sadly, the original fossil skeleton was destroyed during WWII. The latest discoveries of the S. aegyptiacus were in Morocco in 1996, 2014, and 2020. 

Classification and phylogeny of the Spinosaurus – it comes from the family Spinosauridae and belongs to the sub-group Spinosaurinae.

Habitat – The habitat Spinosaurus lived in were waterways in what is now present-day Egypt and Morocco. River deltas, marshes, and wooded inlays were the Spinosaurus’ habitat, and the temperature was humid and sub-tropical. 

Anatomy developed for hunting fish – Crocodile shaped narrow snout with rows of teeth, arms, and claws to enable catching prey once the jaws snapped shut on it. Powerful tail to propel it through the water, similar to modern crocodiles.

Swimming ability – The latest Spinosaurus fossils have yielded almost a complete tail specimen with almost all the vertebrae. It has led to detailed studies that strongly indicate that the Spinosaurus was a strong swimmer and spent most of its time in the water. What was also suggested was that the dinosaur had webbed feet based on fossil evidence. 

Hunting ability and intelligence – The EQ, a measure of intelligence for dinosaurs, is calculated by the dinosaur’s brain’s size compared to its body weight. The Spinosaurus is considered the largest theropod dinosaur. The EQ is estimated to be 1.6-1.8, which is high on the EQ dinosaur chart. It was considerably smarter than a crocodile. As for hunting ability, combined with its intelligence and being a powerful swimmer, and its anatomical adaptations, it would make it an exceptional hunter. 

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The Baryonyx – A Dinosaur That Ate Fish and Lived in Cretaceous Europe

A dinosaur that ate fish and roamed what is now modern-day England is Baryonyx walkeri. Paleontologists found fossilized scales and jaws of the Scheenstia mantelli (a prehistoric fish whose fossils have also been found in Bavaria and France) in the stomach area of Baryonyx fossil. Baryonyx lived in the early Cretaceous period. Its fossils were found in 1983, and it is of significance because it is one of the most complete skeletons of spinosaurids found and one of the most complete theropod skeletons in the UK. 

YouTube Video About the Discovery of the Baryonyx From Surrey, England

Being a theropod dinosaur and a spinosaurid, Baryonyx walked on its hind legs. Its head had a narrow shape like a crocodile, and one of its characteristic features is the large claw on its forearms. It is from this claw that the Baryonyx gets its name – Baryonyx means “heavy claw” in Greek.

Fossils of the Baryonyx – The first fossils of Baryonyx were found in England, and they have subsequently found additional fossils of the dinosaur. Interestingly, the fossilized stomach contents found not only fish scales and jaws but also bones of juvenile iguanodons, which indicates that it ate not only fish but also meat. Baryonyx fossils have also been found on the Isle of Wight, Spain, and Portugal.

Classification and phylogeny – A spinosaurid is classified as from the family Spinosauridae and the sub-family Baryonychinae (cladogram 2018 Arden et al.). 

Habitat – It lived in river deltas and coastal regions of what is now modern-day England and Iberia. In the Cretaceous period in Europe, the landscape was filled with smaller islands, and the larger landmass of what is now the continent of Europe was just a series of the island and coastal inlays. The climate was humid and sub-tropical. 

Anatomy Developed for Hunting Fish – This dinosaur had claws, snout with rows of conical teeth in shape. Paleontologists suggest that the claw from which the dinosaur was named could have been used to hunt fish, similar to how grizzly bears gaff and scoop fish out of the water, standing on the river banks.

Swimming Ability – So far as the fossils indicate, this dinosaur did not spend much time in the water. A theropod dinosaur, it was more suited to land and walked on its hind legs. Still, some paleontologists suggest that the dinosaur may have been semi-aquatic.

Hunting Ability and Intelligence – As for hunting ability for fish, as it wasn’t a strong swimmer, it would have to rely on scavenging fish or, as mentioned above, to gaff fish and scoop them out of the water. The EQ of this dinosaur would sit at 1.6-1.8, as it was a spinosaurid.

The Suchomimus – The Spinosaurid From Africa With an Appetite for Fish

Suchomimus lived during the Early Cretaceous in what is now modern-day Niger in Africa. The dinosaur is a spinosaurid, which shows up notably in its skull shape, which is similar to crocodiles, much like other spinosaurids. The Suchomimus is closely related to the Baryonyx. However, it lived in different geography (Africa instead of Europe).

Here is an organized overview of the Suchomimus, an extinct dinosaur species known primarily for its piscivorous tendencies. The details are summarized in the following table.

Topic	Details	Source
Reason for Piscivorous Diet	Suchomimus is considered a piscivore due to its resemblance to piscivorous crocodiles, including the shape of its snout, teeth, and similar rows of teeth on the upper and lower jaws. Its habitat was also rich in fish, much like the Baryonyx.  (Source)	Paleontological studies
Fossil Discovery	The first Suchomimus fossils were discovered in 1997, yielding about two-thirds of the skeleton, including a giant claw at the thumb position. Subsequent expeditions have unveiled more parts of the Suchomimus tenere and other new fossils.	Fossil records
Classification and Phylogeny	The anatomy of the Suchomimus is extremely close to the Baryonyx walkeri, leading to changes in its classification and phylogeny. It is categorized under the Spinosauridae family and the Baryonychinae sub-family.	Paleontological taxonomy
Habitat	Suchomimus inhabited river deltas and floodplains, mirroring the environment of Niger during the early Cretaceous period, which was hotter and more humid than subtropical climates.	Paleogeography
Anatomy for Hunting Fish	The dinosaur had a giant claw on its forelimbs, similar to a thumb. This was likely used for catching or holding onto fish, analogous to the Baryonyx.	Paleontological morphology
Swimming Ability	Despite its piscivorous nature, Suchomimus had limited adaptations for swimming, even less so than the Baryonyx. However, its skull, snout, and teeth structure made it an efficient fish predator.	Paleontological studies
Hunting Ability and Intelligence	Suchomimus could efficiently hunt and catch fish due to its crocodile-like anatomy. Its estimated EQ (a measure of intelligence) ranges between 1.6 and 1.8.	Paleontological studies

The Liaoningosaurus – The Ankylosaur That Ate Fish

What’s amazing about this dinosaur is that it was an armored dinosaur, like other ankylosaurs, but paleontologists believe it hunted fish. Found in Liaoning province in China, it looks like an ankylosaur or nodosaur on a general level. However, looking more closely at its anatomy, we start to see certain differences.  

Unlike the other three piscivorous dinosaurs that we covered, the Liaoningosaurus was not a spinosaurid. However, because of stomach contents containing what they believe to be fish in the second of only two fossils found, plus its anatomy adaptations, it is considered a fish eater.

Fossils of the Liaoningosaurus – This dinosaur’s fossils, of which there are two known specimens, were found in Liaoning, China. The dinosaur was named in 2001. 

Classification and Phylogeny – The Liaoningosaurus is classified as a basal (primitive) ankylosaur. It represents an early species of ankylosaur. Coming from the Ornithischia branch, the clade of Genosauria includes the ankylosaurs. 

Habitat – The habitat in early Cretaceous China was sub-tropical, with forests, marshes, riverbanks, and deltas. The climate was humid. During that period, the types of plants were conifer trees, cycads, and the vegetation were ferns and the start of flowering bushes.

Anatomy Developed for Hunting Fish – The Liaoningosaurus was a strange ankylosaur, a paradox that is part of its name (Liaoningosaurus parodoxus). Ankylosaurs and Nodosaurs had features that were the opposite of this dinosaur. For instance, its teeth were long and sharp, whereas ankylosaurs had blunt teeth for grinding vegetation. Also, its claws were sharp, and ankylosaurs and nodosaurs had blunt claws. Scientists believe that these features indicated that it hunted fish or was an omnivore (eating meat and plants). As mentioned above, the two fossil specimens contained fish fossils. (Source)

YouTube Video About the Liaoningosaurus

Swimming Ability – One of the reasons the Liaoningosaurus is considered piscivorous was that its body had adaptations that they consider makes the dinosaur semi-aquatic. While we will never know for sure if the Liaoningosaurus could swim and spent half its life in water, scientists point to the lack of a hip fusion, long limbs, and long claws as being adaptations for a semi-aquatic existence.

Hunting Ability and Intelligence – As this dinosaur was an Ornithischia and an ankylosaur, it would have an EQ of about 0.5 which is typical for ankylosaurs. This dinosaur paradoxically is suggested to have been a carnivorous predator, unlike other ankylosaurs, which were all herbivorous because of the shape of its teeth and claws. Whether it actively hunted animals other than fish is not known. 

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Related Dinosaur Articles You Might Also Be Interested In:
Herbivore Dinosaurs – What’s So Cool About Them? (Types, Sizes, Facts)
What Did Omnivorous Dinosaurs Eat? Surprising Facts About Omnivores
What Are Long Neck Dinosaurs (Types, Size, List)?
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What Are the Modern-Day Piscivores and How Do They Compare to Piscivorous Dinosaurs?

Let’s see some of the similarities comparing piscivorous dinosaurs to related modern-day piscivore species. 

List of Modern-Day Piscivores

First, here is a shortlist of some of the animals that are known to be piscivorous today:

Reptiles
● Alligator Gar
● Gharial

Fish
● Barracuda
● Bluefish

Birds
● Penguin
● Bald Eagle

Mammals
● Bottlenose Dolphin
● Sea Lion

The Gharial – A Crocodile-Looking Reptile That Eats Only Fish

After looking at this list, I will take a deep dive into one of the most similar reptiles to the dinosaurs we have been discussing, the Gharial. The Gharial is a crocodilian reptile that lives on the Indian subcontinent. Interestingly, this reptile is known to eat only fish, thus being a true piscivore in terms of the definition.

Classification and Phylogeny – The Gharial is a crocodilian reptile that comes from the family Gavialidae. Spinosaurids are distantly related to crocodiles. 

Habitat – The habitat of the Indian subcontinent is sub-tropical, and the Gharial lives mostly in the water. 

Anatomy Developed for Hunting Fish – As a piscivore, it has a narrow snout and interlocking teeth ideal for catching fish. Like the spinosaurids, they have narrow snout and teeth adapted for hunting fish. 

Swimming Ability – Gharials are excellent swimmers, with their tail being strong and able to maneuver skillfully in rivers and waterways. Paleontologists have studies based on the fossilized tail vertebrae of the Spinosaurus that strongly indicates this dinosaur was a powerful swimmer. (Source)

Hunting Ability and Intelligence – It’s clear to see that the Gharial is a top predator, and its hunting ability to catch fish in the wild is high. In terms of EQ, they fall in with other reptiles at 1.0. I would expect that spinosaurids, at least the Spinosaurus, would have equal hunting abilities, and the EQ is a bit higher. 

Final Thoughts 

It’s cool to know that dinosaurs that ate fish were just as amazing as the herbivore or the omnivore dinosaurs, with specialized anatomy and habitat preferences. 

Naturally, carnivores get the most attention these days as they were apex predators and were fearsome dinosaurs and hunters. 

We can now add to our collection of dinosaur knowledge the amazing fish-eating piscivorous dinosaurs and compare and imagine their swimming and hunting ability.

When we look at the modern-day piscivorous animals like the Gharial, there is a glimpse of what the fish-eating dinosaurs might have been like when alive, with anatomical features developed to hunt and catch fish, powerful swimming adaptations like the Spinosaurus tail. Even the surprise four-legged Liaoningosaurus that chose to eat fish can come alive in our imagination.

It makes me wonder what types of prehistoric fish were plentiful in the inland river deltas and coastal areas of prehistoric Europe, Africa, and China. I’m sure it would be amazing to see a piscivorous dinosaur stomping around in this habitat, now that I know more about them!

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