We have documented elevated tail posture making defensive capability of the tail plausible (Rothschild and Berman 1991), but the head and neck would remain accessible to predator attack.
The question is how did sauropods protect their vulnerable anterior neck region? Could they have used either the neck or the tail as defensive weapons? Lateral motion of the neck is limited to 20 degrees (Steven and Parish, 2005), limiting escape from an attack by swinging its neck out of the way. The tail is sufficiently distant from the head to be of limited value in defense from a frontal attack.
Fossils allow us to understand, speculate about and scientifically test and validate ideas about anatomy, phylogeny (relationships), lifestyle and habitat. Far from being a static field of single points in time, it actually is quite dynamic, frequently allowing a window to the behavior of long extinct animals. But, like all scientific endeavors, it usually ends with a question.
References:
Rothschild, B. M., and Berman, D. S. 1991 Fusion of caudal vertebrae in Late Jurassic sauropods Journal of Vertebrate Paleontology 11:29-36.
Stevens, K. A., and Parish, J. M. 2005. Neck posture, dentition and feeding strategies of Jurassic sauropod dinosaurs. in Tidwell, V., and Carpenter, K. (eds) Thunder-Lizards: The Sauropodomorph Dinosaurs. Indiana University Press, Bloomington, pp. 212-232.
For the rest of the series, follow these links:
https://steemit.com/life/@dinodoc/sauropods-walk-skeletons-talk-part-1
https://steemit.com/steemstem/@dinodoc/sauropods-walk-skeletons-talk-part-2-translating-the-skeleton
https://steemit.com/steemstem/@dinodoc/sauropods-walk-skeletons-talk-part-3-does-the-tail-wag-the-dog
https://steemit.com/steemstem/@dinodoc/sauropods-walk-skeletons-talk-part-4-behavior
https://steemit.com/steemstem/@dinodoc/sauropods-walk-skeletons-talk-part-5
https://steemit.com/steemstem/@dinodoc/sauropods-walk-skeletons-talk-part-6-warm-vs-cold-blooded