Spinosaurus: The Dinosaur with a Sail

Spinosaurus (literally, lizard with spines) was one of the largest carnivorous (meat-eating) dinosaurs ever to walk the earth. Like the other carnivores (meat-eaters), Spinosaurus spent most of its time walking on its hind legs.

The most obvious feature that sets Spinosaurus apart from other carnivorous dinosuars is the distinctive sail that ran the length of its back. This sail or fin was supported by a row of stiff spines, from which Spinosaurus gets its name. At the highest point, the spines of the sail were over six feet long.

What was the purpose of that sail? We really cannot say. The spines have survived, but the soft tissue between them have not. Many paleontologists (dinosaur-scientists) believe that the sail was full of tiny blood vessels, called capillaries. Spinosaurus, which was, we assume, cold-blooded, could have regulated its temperature by turning toward or away from the sun.

Think of the sail as a solar panel, with the warmth of the sun being distributed through the Spinosaurus's body by the blood in the capillaries. This would have given the hunter an advantage in the morning, when other dinosaurs were still sluggish, before they warmed up after a cool night.

Later, in the heat of the day, Spinosaurus could have cooled itself by turning the sail away from the direct sun and letting the wind cool it. Then, the capillaries full of blood functioned like a radiator, to get rid of heat.

Some paleontologists believe that the sail might have been used for display, either to attract a mate or to scare away rivals. Regardless of the color, this gigantic carnivorous dinosaur with its huge sail would have been quite a sight.

Like many carnivorous dinosaurs, Spinosaurus had a huge head, more than six feet long. The rather flat head of Spinosaurus was equipped with powerful jaws that supported a set of smooth, pointed teeth. The teeth were probably not used for chewing but rather for holding the prey.

Perhaps like modern alligators, Spinosaurus swallowed its prey whole. The teeth fit together to keep the prey from escaping. If the prey was too large to swallow in one gulp, then with its long, flexible neck, Spinosaurus could shake its head from side to side to strip off chunks of flesh.

A formidable hunting-machine, Spinosaurus had a lean, muscular body and, despite its great size, an overall lightness of form, so that it could hold up to a lengthy hunt for a range of prey, supported by its huge, muscular hind legs. Like other carnivores that ran on their hind legs, it held its tail up when it ran for balance. The front legs of Spinosaurus were much longer and better developed than the front legs of such carnivores as Tyrannosaurus rex. Spinosuarus probably could have killed some of its prey simply with a blow from a front leg.

When Spinosaurus was discovered in Egypt, only a few bones were found, including a broken jaw, some teeth and a few vertebrae. The bones were transported to Dresden, German, where they were destroyed when the city was bombed during World War II.

Spinosaurus was about twelve meters long. An easy way to work with meters is to remember that three meters equal about ten feet. So, at twelve meters, Spinosaurus was some forty feet long. It lived about 110 million years ago, during the mid-Cretaceous period, in northern Africa.

Spinosaurus first gained public attention when it was pitted against Tyrannosaurus rex (T. rex) in the 2001 film, Jurassic Park III (more). T. rex lost, but he did get an article written about himself (here). Scientists complain that such a battle could never have happened, because Spinosaurus and Tyrannosaurus rex lived in very different regions of the world, during very different times. But, as I have written (here), movies about dinosaurs are for fun, not for facts. You can meet Dimetrodon, a prehistoric animal that is not a dinosaur but that sported a sail similar to Spinosaurus's sail, in my article here.

I have not written an article on dinosaurs in a while. I was inspired to write this article when I read about an upcoming television special on Spinosaurus in an article by Alice Clair Gunkee (source page here), who keeps her readers up to date on what can be seen on television.

You can find an index to my other articles about dinosaurs here.