About
Spinosaurus was a truly bizarre giant — a dinosaur that defied the typical blueprint by becoming a semi-aquatic predator. Growing longer than Tyrannosaurus rex, this North African hunter possessed a 1.75-meter tall along its back, a crocodile-like snout filled with conical teeth, and dense bones that may have helped it sink and walk along riverbeds. Recent discoveries suggest it spent much of its life in water, pursuing large fish like the car-sized coelacanth Mawsonia.
The discovery history of Spinosaurus reads like an adventure novel marked by tragedy. German paleontologist Ernst Stromer discovered the first fossils in Egypt's Bahariya Formation in 1912 and described the species in 1915. Tragically, the original specimen was destroyed when Allied bombs struck Munich's paleontology museum in 1944 during World War II. For decades, scientists had only Stromer's detailed drawings and notes to work from.
The 21st century brought Spinosaurus back into the spotlight. New material from Morocco's Kem Kem beds, including a remarkably complete specimen described in 2014 and a paddle-like tail discovered in 2020, revolutionized our understanding. These finds revealed an animal far stranger than anyone imagined — with short hind legs, a deep tail for swimming, and proportions unlike any other known dinosaur.
Scientific debate continues about just how aquatic Spinosaurus truly was. Some researchers envision it as a pursuit predator swimming after fish, while others see it as more of a wading heron-like hunter. What's certain is that Spinosaurus represents one of the most dramatic examples of a dinosaur adapting to an unexpected ecological niche.
Explore the anatomy
5 featuresThat massive sail running down the back was made of super-elongated bones jutting up from the spine — some reaching 1.75 metres tall, about the height of an adult human! Scientists still argue about what it was for: controlling body temperature, storing fat like a bison's hump, or showing off to other Spinosaurus. Either way, it's an instant giveaway for identifying this dinosaur.
Instead of the knife-like, saw-edged teeth most big meat-eaters had, Spinosaurus had cone-shaped teeth that interlocked like a cage. At the tip of its snout, the teeth fanned outward in a rosette pattern — just like modern gharials and other crocodilians that snag slippery fish. This skull design is a big clue that fish were on the menu.
A stunning 2020 discovery revealed a tail built for swimming — tall, flattened side-to-side, and flexible like a giant newt's. Computer models show it could push through water with serious power. This single find convinced most scientists that Spinosaurus wasn't just wading at the water's edge — it was actively swimming and hunting underwater.
Compared to its body size, Spinosaurus had weirdly short back legs — way shorter than any other giant meat-eating dinosaur. This shifted its weight forward and probably made walking upright on land pretty awkward. But in the water? Buoyancy takes over, so short legs aren't a problem — they actually suggest this animal spent a lot of time submerged.
CT scans revealed something surprising: Spinosaurus bones are unusually dense and solid, with less spongy marrow inside than typical dinosaurs. This same adaptation — called pachyostosis — shows up in manatees and hippos today. The extra weight acts like a diver's belt, helping the animal sink and stay on the riverbed instead of bobbing at the surface.
Where fossils were found
Kem Kem Group
Drâa-Tafilalet, Béchar · Morocco, Algeria
110.1–93.9 million years ago(16.2m year span)
Where Spinosaurus Roamed
During the mid-Cretaceous period, Spinosaurus inhabited the coastal river systems and tidal flats of northern Africa, part of the fragmenting supercontinent Gondwana, where lush deltaic environments bordered the southern margins of the ancient Tethys Sea. This warm, humid region featured vast mangrove-lined waterways teeming with giant fish and coelacanths, creating an ideal hunting ground for this semi-aquatic apex predator.
Keep exploring the vault
Ouranosaurus
Ouranosaurus nigeriensis
Spinosaurus inhabited the same general North African region during the Early-Mid Cretaceous.
Carcharodontosaurus
Carcharodontosaurus saharicus
Both Spinosaurus and Carcharodontosaurus are known from the Kem Kem Beds of North Africa (Morocco/Algeria), dating to the Cenomanian stage.
Baryonyx
Baryonyx walkeri
Baryonyx and Spinosaurus are both spinosaurids that independently developed elongated crocodile-like snouts, conical teeth adapted for fish-catching, and semi-aquatic lifestyles.
Suchomimus
Suchomimus tenerensis
Same family: Spinosauridae
Irritator
Irritator challengeri
Same family: Spinosauridae
Rugops
Both species co-occurred in the Kem Kem Formation of North Africa during the mid-Cretaceous.