Great Sauropods Wallow in a Watery World

In October 1877, Yale University paleontologist Othniel C. Marsh uncrated what were supposed to be the remains of a giant ground sloth. Instead he found parts of a Brontosaurus (now Apatosaurus). The railroad men who sent the bones from Como Bluff in Wyoming were admittedly not geologists, but Marsh was doubtless happier to have a new dinosaur than the already-known Megatherium.

The fresh fossils spurred the great Western American dinosaur race between Marsh and his rival, Edward D. Cope of Philadelphia. Plundering the badlands of bones was far more urgent than ecological study: it was readily accepted that fossil-laden sediments were bygone seashores and lake bottoms.

So began a long effort to portray creatures like Diplodocus, Camarasaurus, and Barosaurus (which Marsh labeled "sauropods" for their five-toed, lizard-like feet) as behemoths comfortable only in water, the Jurassic equivalent of a hippo. Although scientific debate may have revolved around interpretations of anatomy, it was predicated on the unshakable 19th-century assumption that the Age of Reptiles was also the Age of Swamps.

Confronted with imagining how animals weighing up to 80 tons could possibly stand, the easiest answer was to float them. This was suggested by the fact that sauropod nostrils sit on top of their heads, as do those of modern-day whales or Mesozoic Era ichthyosaurs. Once submerged, sauropods could feed on water plants and raise their snorkel-like necks to breathe at the surface, safe from dry-land predators.

The last attempt to lead the sauropods to water was a literal contortion act. In 1883 Marsh restored Brontosaurus in the manner of an elephant, putting the legs directly under its massive body. But after the turn of the century, a short-lived movement began to portray Diplodocus, of the same family, as a creeping crocodile. Carnegie Museum curator W.J. Holland dismissed the sprawling pose in 1910 as a "skeletal monstrosity" which would have required the animal to drag its ribcage in a deep rut!

It would be decades before Cope's first intuition, that the Jurassic giants used their long necks to browse the treetops like giraffes, again resurfaced. For that they needed some dry land.