What did Spinosaurus eat, and how do we know? The answer comes from a combination of clues: its teeth, its skull, its bones, chemical signals locked in its enamel and the fossils of the animals that shared its rivers. Together, Spinosaurus fossils paint a picture of a giant predator built around water and fish, but not limited to them.
This article explores the evidence for the Spinosaurus diet, the river world it hunted in and the fossils collectors can own today.
The river world of Spinosaurus
Spinosaurus lived around 100 to 95 million years ago in North Africa. Its best fossil record comes from the Kem Kem beds of southeastern Morocco, which formed in a huge river system flowing toward the sea.
Those rivers were full of large fish. The coelacanth Mawsonia grew to several metres long. Onchopristis, a sawfish-like fish, had a long snout lined with barbed teeth. Lungfish, bony fish and sharks were also common. For a large predator able to work in and around water, this was an enormous food supply.
Clue 1: the teeth
Spinosaurus teeth are tall, conical and round in cross-section, with fine flutes and very small serrations. They are built to pierce and grip rather than slice. This design is shared by many unrelated fish-eaters, from gharials to ancient marine reptiles, and it is one of the strongest signs that fish were central to the Spinosaurus diet.
Clue 2: the skull
The skull of Spinosaurus was long and narrow, much like a crocodile’s. A narrow snout moves quickly through water with little resistance, which suits snapping at fast-moving fish. The front of the jaws held an interlocking rosette of large teeth that formed an effective trap. The nostrils sat far back on the snout, away from the tip.
Clue 3: chemistry in the enamel
Scientists can read a predator’s lifestyle from the chemistry of its teeth. Studies of oxygen isotopes in spinosaurid teeth found values closer to those of crocodiles and turtles than to land-living theropods. That suggests Spinosaurus and its relatives spent much of their time in or near water, where they found much of their food.
Clue 4: the bones
Spinosaurus had unusually dense bones, a feature also seen in many animals that spend time in water, such as penguins and hippos. Dense bones reduce buoyancy and may have helped it stay submerged.
In 2020, scientists described a tall, paddle-like tail from the Kem Kem and argued that Spinosaurus was an active swimmer that pursued prey underwater. Other researchers have since argued that it was mainly a wading hunter that stalked fish in the shallows, like a giant heron. This debate is ongoing, but both sides agree that water and fish were at the heart of its life.
Clue 5: its relatives
Related spinosaurs offer direct evidence of what these predators ate. Baryonyx, a spinosaur from England, was found with fish scales in its stomach area, along with bones from a young plant-eating dinosaur. In Brazil, a spinosaurid tooth was found lodged in a pterosaur bone.
These finds show that spinosaurs were fish specialists but also opportunists. Spinosaurus probably took small dinosaurs, pterosaurs and carcasses when the chance arose.
Putting the diet together
The evidence points to a predator that relied heavily on fish, especially large river fish, while taking other prey opportunistically. Its teeth gripped, its snout moved quickly through water, and its body was adapted for life on the river’s edge or in the water itself.
That makes Spinosaurus one of the most unusual large predators in the history of life on land.
Spinosaurus fossils collectors can own
Most Spinosaurus fossils available to collectors are teeth from the Kem Kem beds. They are the most accessible and most recognisable part of the animal.
Other Spinosaurus fossils occasionally appear, including vertebrae, fragments of the tall neural spines that supported the sail, hand claws and jaw sections. These are far rarer than teeth and often need more preparation or restoration, so careful description from the dealer is essential. Browse related material in the dinosaur bones and dinosaur claws categories.
To build a complete “river world” display, pair a Spinosaurus tooth with fossils of the animals it shared the rivers with. Pterosaur and crocodilian teeth from the pterosaurs, sauropods and crocodiles category are a natural addition.
Frequently asked questions
1. What did Spinosaurus eat?
Fish made up a large part of its diet, especially big river fish, but it probably also ate other prey such as small dinosaurs and pterosaurs.
2. How do scientists know Spinosaurus ate fish?
From its conical teeth, crocodile-like snout, water-adapted bones, chemical signals in its teeth and evidence from related spinosaurs.
3. Could Spinosaurus swim?
It was strongly tied to water, but scientists still debate whether it was an active swimmer or mainly a wading hunter.
4. What Spinosaurus fossils can collectors buy?
Mostly teeth from the Kem Kem beds of Morocco. Bones, claws and jaw fragments are much rarer.
Bring the river predator home
Every Spinosaurus fossil is a clue to how this giant hunted in ancient African rivers. A single tooth carries that story onto your shelf. Explore authentic Spinosaurus fossils and other Moroccan dinosaur fossils at Buried Treasure Fossils.