Spinosaurus vs. Sarcosuchus - Who Wins?

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Spinosaurus vs. Sarcosuchus

sarcosuchus spinosaurus
Left, Spinosaurus (Flickr); Right, Sarcosuchus (Flickr).

During the middle Cretaceous period, about 100 million years ago, northern Africa was home to two of the biggest reptiles ever to walk the earth. As far as we know, Spinosaurus was the largest carnivorous dinosaur that ever lived, outweighing the much later Tyrannosaurus Rex by one or two tons, while Sarcosuchus (also known as SuperCroc) was twice the length of the largest modern crocodiles and ten times as heavy. Who would win a head-to-head battle between these prehistoric giants? (See more Dinosaur Death Duels.)

In the Near Corner - Spinosaurus, the Sail-Backed Assassin

Measuring about 50 feet long from head to tail and weighing in the neighborhood of nine or 10 tons, Spinosaurus, and not T. Rex, was the true king of the dinosaurs. Over and above its impressive girth, though, the most notable feature of Spinosaurus was the prominent sail on its back, supported by a network of five- and six-foot-long "neural spines" that jutted out of this dinosaur's vertebral column. What's more, we now have evidence that Spinosaurus was a semi-aquatic, or even a fully aquatic, dinosaur, meaning that it was an accomplished swimmer as well (and may have hunted prey in crocodile-like fashion).

Advantages. Unlike most other theropod dinosaurs, Spinosaurus possessed a long, narrow, crocodile-like snout that would have been extremely dangerous in close combat, more like a tapered sword than a blunt hatchet. Also, there's some speculation that Spinosaurus may have been an occasional quadruped--that is, it spent most of its time on its two hind legs, but was also able to get down on all fours when circumstances demanded--giving it an extremely low center of gravity in a tussle. And did we mention that this theropod was an agile swimmer?

Disadvantages. As impressive as Spinosaurus' sail was, it might have been a positive hindrance during a battle with Sarcosuchus, which could chomp down on this flat, sensitive, fragile flap of skin and bring its opponent crashing to the ground (kind of like a professional wrestler yanking his adversary's long, golden locks). Also, part of the reason Spinosaurus had such a distinctive snout is that it spent most of its time feeding on fish, not on other dinosaurs or giant crocodiles, so presumably this theropod wasn't accustomed to having to fight for its food.

In the Far Corner - Sarcosuchus, the Killer Cretaceous Crocodile

What can you say about a crocodile that measured 40 feet from head to tail and weighed in the neighborhood of 10 to 15 tons? Not only was Sarcosuchus the biggest prehistoric crocodile that ever lived, but it was the biggest reptilian meat-eater of the Mesozoic Era, outweighing even Spinosaurus and Tyrannosaurus Rex. Even more impressively, this "flesh crocodile" seems to have kept growing throughout its lifetime, so superannuated individuals may have outweighed two Spinosaurus adults put together.

Advantages. As big as it was, like other crocodiles Sarcosuchus kept a very low profile: this Cretaceous predator spent most of its day half-submerged in shallow rivers, lunging out of the water when thirsty dinosaurs, birds and mammals ambled nearby for a drink. Like Spinosaurus, Sarcosuchus was equipped with a long, narrow, tooth-studded snout; the difference was that, as an omnivorous crocodile, Sarcosuchus' jaw muscles far outclassed those of the fish-eating Spinosaurus in biting force per square inch. And as a crocodile, of course, Sarcosuchus was built very low to the ground, making it all that much harder to topple from its splayed feet.

Disadvantages. A crocodile as big and ungainly as Sarcosuchus couldn't have been exceptionally spry; after its initial, lunging surprise attack on its prey, it probably ran out of steam fairly quickly. To put it another way, Sarcosuchus almost certainly possessed an ectothermic (cold-blooded) metabolism, while there's an increasing amount of evidence that theropods like Spinosaurus were endothermic, or warm-blooded, and thus were capable of generating much more energy over longer periods of time (which may have aided their stamina in a to-the-death fight).

Fight!

Since there's no way even a desperately hungry Spinosaurus would go out of its way to attack a full-grown Sarcosuchus, let's imagine a more plausible scenario: Spinosaurus stomps down to a nearby river for a drink, clumsily jostling a contented, floating Sarcosuchus with its unwieldy snout. Reflexively, Sarcosuchus lunges out of the water and grabs Spinosaurus by its hind foot; the big theropod quickly loses its balance and splashes into the river. Thrashing about wildly, Spinosaurus manages to dislodge its bleeding foot from Sarcosuchus' jaws; then the big crocodile suddenly disappears, submerging below the surface of the water. For a moment, it seems as if Sarcosuchus has abandoned the fight, but then it suddenly lunges again, aiming for the one weak point on Spinosaurus' body.

And the Winner Is...

Sarcosuchus! The giant crocodile snaps its jaws shut on Spinosaurus' ample neck, then holds on for dear life, its ten-ton bulk an ample counterweight against the desperate flailing, lunging and jerking of its slightly less massive adversary. Quickly suffocated--remember, warm-blooded dinosaurs require much more oxygen than cold-blooded crocodiles--Spinosaurus lands with a thud in the Sahara mud, and Sarcosuchus laboriously drags its twitching carcass the rest of the way down into the water. Ironically, the big crocodile isn't even hungry: it had already chowed down on a tasty baby titanosaur just before Spinosaurus interrupted its slumber!

Do you agree with the outcome of this battle? Do you disagree? Check out what other readers have to say!

Readers Respond - The Case for Spinosaurus