Diplodocus (Greek for "double beam"); pronounced dip-LOW-doe-kuss
Plains of North America
Late Jurassic (155-145 million years ago)
Size and Weight:
About 100 feet long and 15-25 tons
Long neck and tail; thick body; long, slender teeth
The classic Monty Python sketch was actually about Brontosaurus (now known as Apatosaurus), but it applies just as well to Diplodocus. A very nervous-looking paleontologist appears on a talk show to discuss her latest theory. After much hemming and hawing, she finally comes out with it: dinosaurs were "Thin at one end, much much thicker in the middle, and then thin again at the far end." The general description is accurate, but the exact size of Diplodocus is still a matter of dispute; adults may well have reached over 150 feet in length, but since most of that consisted of neck and tail the total weight of this dinosaur may have been as little as 15 to 25 tons. (See 10 Facts About Diplodocus and a gallery of Diplodocus pictures.)
The prototypical sauropod, Diplodocus is well known from its numerous fossils, though paleontologists still can't quite agree on how it fed. The most widely accepted theory (based partly on analysis of this herbivore's teeth) is that it methodically stripped tree branches of their leaves, all day, every day (a multi-ton dinosaur had to eat a lot every day to maintain its weight). It's still unknown, though, whether Diplodocus held its head proudly in the air, or kept it level to the ground--where it still could have feasted on low-lying leaves.
You may be amused to know that Diplodocus owes much of its popularity to the late 19th century "robber baron" Andrew Carnegie, who made his fortune in the steel industry. Carnegie was so entranced by this huge dinosaur that he commissioned a series of full-sale reconstructions, which he shipped to natural history museums across the world, from England to Argentina. As you might guess, one of the most famous of all Diplodocus casts is located in Carnegie's home city, in Pittsburgh's own Carnegie Museum of Natural History.