Where Did Spinosaurus Live and What Was Its Habitat?

Spinosaurus lived in what is now North Africa, primarily in the region that spans modern-day Morocco and Egypt, during the mid-Cretaceous period roughly 95 to 100 million years ago. Its habitat was a vast, river-laced lowland dotted with floodplains and occasional brackish waterways, far removed from the arid Sahara that covers the region today. The picture of its world has become richer and more contentious over the past decade, as new fossils and new analytical techniques have sharpened and complicated our understanding of just how closely this animal’s life was tied to water.

The Kem Kem Beds and What the Rocks Reveal

Most Spinosaurus fossils come from the Kem Kem Group, a sequence of sedimentary rocks exposed along the border of Morocco and Algeria in southeastern Morocco. These deposits date to the Cenomanian stage of the Late Cretaceous, roughly 100 to 93 million years ago. Researchers who have studied the Kem Kem beds agree that the sediments are continental in origin, meaning they were laid down on land rather than under an open sea, but they differ on the finer details. Some interpret the deposits as mainly fluvial, meaning rivers and their surrounding floodplains dominated the landscape, while others see more of a deltaic system with occasional lake environments scattered through it. A third interpretation describes the area as mostly terrestrial with pockets of brackish and freshwater deposits.¹

What all these interpretations share is the image of a landscape defined by water. Picture broad, slow-moving rivers winding through tropical lowlands, flanked by mudflats and sandbars, with seasonal flooding expanding the waterways across wide floodplains. The fossil record from the Kem Kem beds is remarkably rich, containing not just dinosaurs but also sharks, large sawfish, coelacanths, lungfish, crocodile relatives, turtles, and an extraordinary diversity of pterosaurs. The pterosaur assemblage alone is one of the most diverse ever found in any river-deposited sediment.² That kind of diversity points to a productive ecosystem flush with aquatic and semi-aquatic life, the sort of environment where a large fish-eating predator could thrive.

Why North Africa Was So Wet

The Sahara Desert did not exist in Spinosaurus’s time. During the mid-Cretaceous, global sea levels were among the highest in Earth’s history, and northern Africa sat in a particularly low-lying position. The continent was drifting northward, away from the buoyant mantle regions that had kept parts of it elevated. This dynamic subsidence amplified the effects of rising sea levels, and the result was maximum inundation of northern Africa during the Cenomanian and Turonian stages, exactly the time window when Spinosaurus roamed the landscape.³

In practical terms, much of what is now dry desert was then a coastal margin or low-lying floodplain. The Tethys Sea, a precursor to the modern Mediterranean, lay to the north and periodically encroached inland. Rivers drained southward and westward into broad basins. The climate was hot and likely seasonal, with periodic wet and dry phases that would have swelled and contracted the river systems Spinosaurus depended on. This is not a speculative backdrop painted for drama; the geology of the Kem Kem beds preserves it directly in the types of sediment, the fossil fish assemblages, and the geochemistry of the rocks themselves.

A Landscape Crowded with Giant Predators

One of the strangest features of the Kem Kem ecosystem is just how many enormous predatory dinosaurs lived there at the same time. Spinosaurus shared its habitat with Carcharodontosaurus, a massive theropod roughly the size of Tyrannosaurus, as well as other large predators like Deltadromeus. Having multiple apex predators of that size in one ecosystem seems paradoxical. Modern ecosystems rarely support more than one or two large predator species in the same area, and when they do, those predators tend to hunt very different prey.

That is exactly the explanation most researchers favor: niche partitioning. Spinosaurus likely occupied a different ecological role than its terrestrial neighbors. It focused on aquatic prey, particularly fish, while Carcharodontosaurus and others hunted land-dwelling animals like sauropods and ornithopods. Modeling work has suggested that these large predators could coexist as long as each had access to exclusive food sources. Without those exclusive sources, one predator would eventually outcompete and displace the others.⁴ The idea is reinforced by the observation that the Kem Kem beds contain an “overabundance” of giant theropods, a situation best explained by Spinosaurus being semi-aquatic or fully aquatic while the other large carnivores stuck to a more conventional land-based lifestyle.⁵

Scavenging likely played a role, too. Carrion from large animals dying along river margins would have been available to all the predators in the ecosystem, creating a shared food resource that supplemented each species’ primary diet. The picture is less like lions and cheetahs competing on an open savanna and more like a brown bear fishing a salmon run while wolves hunt elk in the surrounding forest. Overlap existed, but not enough to prevent coexistence.

How the Skeleton Points to Water

The argument that Spinosaurus was tied to aquatic habitats does not rest solely on where its bones were found. Its body shows a suite of unusual features that make little sense for a purely land-based predator. Most large theropods have hollow limb bones with open internal cavities, which reduce weight for fast movement on land. Spinosaurus’s limb bones are solid, lacking those open cavities entirely. Its pelvic girdle is small compared to other theropods of its size, and its hind limbs are proportionally short.⁶ Dense, solid bones are a well-known adaptation in animals that spend significant time in water, because they act as ballast, helping the animal control buoyancy and stay submerged rather than bobbing on the surface.

The snout offers another line of evidence. Spinosaurus had an elongated, narrow rostrum with a distinctive rounded tip sometimes called a “rosette,” reminiscent of the snouts seen in modern gharials and other fish-eating crocodilians. Recent work examining the neurovascular system inside this rosette found an elaborate, densely branching network of canals and large foramina on the snout surface. The volume and complexity of this vascular system are consistent with the hypothesis that Spinosaurus had hypersensitive skin on its snout, possibly equipped with specialized sensory organs similar to those found in crocodilians.⁷ Crocodilians use their equivalent organs to detect pressure changes in water, allowing them to sense the movement of nearby fish and strike with precision even in murky conditions. If Spinosaurus had something similar, it would have been well-equipped for hunting in the turbid rivers of the Kem Kem landscape.

The Debate Over How Aquatic Spinosaurus Really Was

While the general picture of Spinosaurus as a water-associated predator has broad support, the question of how deeply aquatic it was remains genuinely contested. Some researchers have argued that it was a fully submerged underwater forager, diving beneath the surface to chase fish the way a cormorant or a penguin does. Others see it as more of a wading hunter, standing in shallow water and using its long arms and sensitive snout to snatch fish from above, closer to how a heron feeds. A third camp holds that even the wading model overstates the case and that Spinosaurus was primarily terrestrial, just with a strong dietary preference for fish.

Much of this debate centers on bone density data. A high-profile study used a statistical method to classify Spinosaurus as a “subaqueous forager” based on the compactness of its femur and rib bones. However, a thorough reexamination of the datasets and analytical methods behind that conclusion identified substantial problems, including issues with the data itself, the statistical assumptions, and the way the method was applied. That critique did not necessarily prove Spinosaurus was terrestrial, but it argued that the specific evidence used to call it a deep-diving underwater hunter was unreliable.⁸

The honest state of the science is somewhere in the middle. The solid limb bones, reduced hind limbs, paddle-like tail (described in a 2020 study that generated enormous excitement), crocodilian-like snout, and sensory adaptations all point to an animal with a strong connection to water. Whether that connection meant full submersion or shallow-water ambush hunting is where the uncertainty lives. The most recent synthesis of spinosaurid evolution describes the latest spinosaurines, including Spinosaurus, as “shallow water ambush specialists,” a framing that splits the difference and fits the available evidence reasonably well.⁹

Spinosaurus Beyond Morocco

Although the Kem Kem beds of Morocco have produced the most material, the original Spinosaurus fossils were actually found in Egypt. The German paleontologist Ernst Stromer described Spinosaurus aegyptiacus in 1915 from specimens collected in the Bahariya Formation of the Western Desert, a deposit roughly contemporaneous with the Kem Kem beds. Those original fossils were destroyed during the Allied bombing of Munich in 1944, which is why Morocco has become the primary source of new material. The Bahariya Formation preserves a similar environment to the Kem Kem beds: coastal, river-influenced, and rich in aquatic life.

The Kem Kem beds themselves have yielded evidence of at least two distinct spinosaurine species, not just one. Analysis of isolated quadrate bones (a bone at the jaw joint) from the Kem Kem revealed two clearly different morphotypes, indicating that Spinosaurus shared its North African rivers with a close relative.¹⁰ How two large, fish-eating spinosaurids divided resources in the same river system is an open question, but it reinforces the idea that the Kem Kem waterways were productive enough to support multiple large aquatic predators.

Looking beyond North Africa, Spinosaurus’s broader family had a wide geographic reach. The spinosaurid clade includes genera found across multiple continents, and the group’s evolutionary radiation coincided with the opening of the Atlantic Ocean. During the final phase of this radiation, which began just before the Late Cretaceous, spinosaurines reached their maximum body size as shallow-water ambush specialists, but their geographic range was limited to northern Africa and South America.⁹ Earlier members of the family had broader distributions. Fossils from the Iberian Peninsula, for instance, show that spinosaurids favored freshwater environments with some marine influence in what is now Spain, during the earlier Barremian stage.¹¹ The consistent thread across all these locations is water. Wherever spinosaurids show up in the fossil record, they show up near rivers, deltas, and coastal margins.

What the Fish Tell Us

One underappreciated line of evidence for understanding Spinosaurus’s habitat comes from the fish it likely ate. The Kem Kem beds preserve a remarkable fish fauna that includes large coelacanths (Mawsonia, with individuals exceeding a meter in length), giant sawfish, lungfish, and various ray-finned fish. This assemblage is dominated by species adapted to freshwater or brackish conditions, with relatively few purely marine forms. The presence of lungfish is particularly telling, because lungfish are freshwater animals with the ability to survive dry periods by burrowing into mud, suggesting that the rivers and floodplains of the Kem Kem underwent seasonal drying.

For Spinosaurus, this fish community would have provided a rich and reliable food source during wet periods but potentially a challenging one during dry seasons. A large predator dependent on fish in a seasonal environment may have needed to range widely along river corridors to find permanent water, or it may have switched to opportunistic scavenging during lean times. This is speculative, but it connects to the broader ecological modeling that suggests scavenging was an important supplementary strategy for Kem Kem predators.

A Lost World Under the Sand

The Kem Kem beds sit today in one of the most inhospitable stretches of the Sahara, along the edge of a series of escarpments in southeastern Morocco. Fossil collectors, both professional and commercial, have worked the exposures for decades, and the region has become one of the world’s most productive sites for Cretaceous vertebrate fossils. That productivity comes with complications. Many specimens reach the scientific community through commercial fossil dealers rather than controlled excavations, which means precise location data and stratigraphic context are sometimes lost. Researchers have to work with what they have, and what they have is often a spectacular bone with a vague provenance.

Despite those challenges, the cumulative picture from the Kem Kem beds is remarkably coherent. The sediments, the fossil assemblages, the geochemistry, and the anatomy of the animals themselves all converge on the same basic story: a hot, low-lying landscape laced with rivers and floodplains, teeming with aquatic life, and home to a predator community unlike anything in the modern world. Spinosaurus was the largest and strangest member of that community, an animal whose body was shaped by and for the water even as it walked on land. Its habitat was not a single pond or a single stretch of river but an entire riverine ecosystem stretching across hundreds of kilometers of what is now desert, a landscape so thoroughly erased by time and tectonic change that only the bones and the rocks preserve any trace of it.