The dinosaur formerly known as Brontosaurus, Apatosaurus was one of the first sauropods ever to be discovered and described. Here are 10 facts you may (or may not) have known about this famous plant-eater. (See also a gallery of Apatosaurus pictures.)
1. Apatosaurus used to be known as Brontosaurus.
In 1877, the famous paleontologist Othniel C. Marsh bestowed the name Apatosaurus on a new breed of sauropod--and two years later, he did the same for a second fossil specimen, which he named Brontosaurus. Later, it was determined that the two fossils belonged to the same genus--so the name Apatosaurus had priority, even though Brontosaurus had become more popular. (See a detailed fossil history of Apatosaurus.)
2. The name Apatosaurus means "deceptive lizard."
The name Apatosaurus wasn't inspired by the mixup described above; rather, Othniel C. Marsh was referring to the fact that this dinosaur's vertebrae resembled those of mosasaurs, the sleek, vicious marine predators (only distantly related to dinosaurs) of the late Cretaceous period. You can imagine why Brontosaurus, Greek for "thunder lizard," wound up having more traction with the general public!
3. Apatosaurus was a close relative of Diplodocus.
Apatosaurus was discovered in the same year as Diplodocus, yet another gigantic sauropod named by Othniel C. Marsh. These two dinosaurs were closely related, but Apatosaurus was more heavily built, with stockier legs and differently shaped vertebrae. Oddly enough, despite the fact that it was named first, Apatosaurus is still classified as a "diplodocid" sauropod!
4. Full-grown Apatosaurus adults weighed about 25 to 40 tons...
As horrifyingly huge as Apatosaurus must have seemed to 19th-century dinosaur enthusiasts, it was actually moderately sized for a sauropod, only measuring about 75 feet from head to tail and weighing in the neighborhood of 25 to 40 tons (compared to lengths of over 100 feet and weights in excess of 100 tons for behemoths like Seismosaurus and Argentinosaurus).
5. ...but their hatchlings were light enough to run on two feet.
Recently, researchers in Colorado discovered the preserved footprints of a herd of Apatosaurus. The tinier trackmarks were made by hind (but not front) feet, conjuring up the image of 5- to 10-pound Apatosaurus hatchlings skittering on their two hind legs. If this was truly the case, then it's likely that all sauropod babies and young juveniles ran this way, the better to elude hungry theropods.
6. Apatosaurus was the first-ever cartoon dinosaur.
In 1914, Winsor McCay--best known for his comic strip Little Nemo in Slumberland--premiered Gertie the Dinosaur, a short animated film featuring a realistically hand-drawn Brontosaurus. Since then, Apatosaurus (in the guise of its more popular name) has been featured in countless Hollywood movies, with the odd exception of the Jurassic Park series and its preference for Brachiosaurus.
7. Scientists once thought that Apatosaurus lived underwater.
The long neck of Apatosaurus, combined with its unprecedented weight, greatly confused 19th-century naturalists. As was the case with Diplodocus, some paleontologists tentatively proposed that Apatosaurus spent most of its time underwater, holding its neck out of the surface like a gigantic snorkel (and perhaps looking a bit like the Loch Ness Monster).
8. Apatosaurus may have wielded its tail like a whip.
Like most sauropods, Apatosaurus possessed a long, thin tail that acted as a counterweight to its equally long neck. Based on the lack of characteristic trackmarks, paleontologists believe that Apatosaurus held its tail off the ground, and it's possible (though far from proven) that this dinosaur "whipped" its tail at high speeds to deter or even inflict wounds on curious predators.
9. No one knows how Apatosaurus held its neck.
Paleontologists are still debating the posture of sauropods like Apatosaurus: did this dinosaur hold its neck at the full possible height (which would have entailed its having a warm-blooded metabolism, to pump all that blood 30 feet into the air), or did it hold its neck parallel to the ground, like the hose of a gigantic vacuum cleaner? The evidence, it's disappointing to report, is still inconclusive.
10. At least one paleontologist wants to bring back "Brontosaurus."
Many scientists still lament the demise of Brontosaurus, a name familiar to them from their childhoods. Robert Bakker, who's a bit of a maverick in the paleontology community, has proposed that Othniel C. Marsh's Brontosaurus deserves to be assigned to its own genus after all, and shouldn't be lumped in with Apatosaurus. Don't expect this change to happen any time soon, if ever!