sauropods

Reconstructing how the largest land vertebrates looked and lived is a fascinating challenge requiring integrating knowledge and skill from multiple scientific disciplines. All too often, modern animals are used as superficial analogs or models for their form and behavior. The work described on these pages primarily address the osteological structure of their necks, but also discuss characteristic poses of modern vertebrates, and beliefs held about sauropod neck posture.

The sauropod neck is the most curious feature of these unique creatures. When their individual vertebrae are fitted together they form an improbably straight extension of the back. Consequently:

Those sauropods with those with shorter forelimbs than hind limbs hence roughly horizontal backs had necks that emerged as horizontal extensions of the back.

Those sauropods with roughly equal-length limbs had slightly upward sloping backs backs, and the neck also sloped upward as it emerged from the back

At the head end of the neck, virtually all sauropod specimens exhibit a slight downturn to the neck, resulting in a slight droop which positioned the head well for feeding downward, either for low browsing, medium, or high browsing (depending on the bauplan). Contrary to popular belief, the vertebral column does not bend upward at the base of the sauropod neck as it does most famously in the giraffe.

Most modern bird and mammal necks are more-or-less sigmoid curved. The vertebrae are keystone-shaped and fit together to make a reflex curve that intrinsically raises the head above the shoulders in the undeflected state. To be sure, such animals frequently lift the head even higher by bending the neck up at the base, and some nervous creatures habitually add this additional elevation when they are not busy eating (especially grazers such as bunnies and ostriches, given the nature of foxes and lions). Now, regarding sauropods, their necks are osteologically very straight, and perhaps unaesthetic to some, and contrary to their childhood images and rubber dinosaur collection. But sauropods were what they were, and there is no close modern analog for these great creatures. But to ascribe living behavior to these extinct creatures based on extant analogues, it is important to choose the modern models with care. There are vertebrates today that are very large herbivores. Good. Very few mammals, even fewer birds, but many reptiles have straight cervical vertebral columns. It is important to study animals whose necks are not sigmoid curved and instead stick straight out from the shoulders. (Basically, if they wanted to raise their necks a lot, they'd have the necessary bends built in. Those that don't, well, don't.) So it's not easy to find a modern model. A bunny, for instance, would not be the very model of a modern major sauropod.

1. Bunny for Brontosaurus*

How did sauropods pose those straight necks? Well, how do various vertebrates today characteristically hold their heads while engaged in feeding, locomotion, and just hanging around? How do you believe sauropods held their heads?

2. we're talking straight, and kind of droopy like

While the necks of most birds and many mammals form a sigmoid or reflex curve, sauropod necks just hang out there, sort of droopy like.

3. straight talk about sauropod necks

Join the distinguished-yet-affable Charles Gilmore (right), John Bell Hatcher, Carl Wiman, and Werner Ernst Martin Janensch for lunch and some straight talk.

(Charles Gilmore, 1924; photo: Shorpy)

4. Apatosaurus

Apatosaurus louisae (CM 3018) studied through digital techniques to reconstruct the neck osteology, the reachability envelope achievable by the neck, some details of the re-mounting process for Apatosaurus louisae (CM 3018), and a kinematic exploration of its walking gait.

5. Brachiosaurus

This sauropod was initially mounted with sufficient plaster and artistic license to bend the neck upwards giraffe-style, although the actual fossil vertebrae provide no evidence that the neck was other than a straight extension of the back.

6. Camarasaurus

This sauropod is often depicted with a vertical neck, largely from misinterpretation of the death pose of a juvenile specimen, contrary to the many specimens with articulated vertebral columns that suggest the neck emerged straight at the shoulders.

7. Dicraeosaurus

Dicraeosaurus has a short neck that matches its diplodocoid character of shorter forelimbs than hind limbs. But unlike the dorsal vertebral columns of Apatosaurus and Diplodocus, which are now recognized to have substantially straight backs, those of Dicraeosaurus form a slight arch, which created a downward slope at the base of the neck. This slope continues into the neck, suggesting strong specialization for low browsing.

8. Diplodocus

This diplodocid had a longer neck than that of its sister taxon Apatosaurus, yet could not raise its head as high. It could reach far above shoulder height (contrary to some false statements made of our research), but was more specialized for reaching laterally and downward than upward.

9. Euhelopus

Originally reconstructed with its neck in precisely the same pose as found, it is still often regarded as a high browser. But the vertebrae at the base of the neck are dorsiflexed in the frequently occurring death pose. Remove the postmortem dorsiflexion and voilá, another low browser.

10. Manenchisaurus

How could it have raised its bizarrely long neck, as sometimes depicted? The cervical vertebrae (such as C18, shown here) do not form an upturn at the base, contrary to some silhouette illustrations, and the low neural spines of the dorsal vertebrae would provide poor mechanical advantage for raising. Think low browser instead.

11. Angloposeidon

One big cervical vertebra of clearly brachiosaurid morphology. Impressive, but which cervical was it? It's grandeur hinges on that estimate.