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Re: Sauropod Neck

John Schneiderman said:

I see only about 45 degrees of arc (side to side or and up and down) if
the mounts of (non-brachiosaur) sauropods are correct.  I see sauropods as
constantly moving foragers (browsing on whatever plants they approach).

I'll have to post the Parrish and Stevens ref tomorrow. Diplodocus does have a more restricted side to side motion, but Apatosaurus has a large arc of motion. The motion of ventriflexion (bending the neck down) is very great in both Diplodocus and Apatosaurus, so they're necks are very flexible in that plane. Again, I will post the ref tomorrow.

Trackways attributed to sauropods suggest herding behavior, so masses of animals on the move (in about the same direction) have little opportunity for or need of a wider degree of arc for browsing. And there is the "knock-down" the tree method of getting to the canopy of leaves. Just strip, swallow and move on.

Sure, but this assumes a number of things. Sauropods may not have been all that fast. So, they were probably on the move, but how fast they were moving would make a huge difference in how they would feed. If you can stand still and just use your neck to forage, you would save a lot more energy than if you quickly walked by getting what you could. You could, of course, knock down trees, but this is assuming there would be enough of a meal there to do it. Imagine a group of large sauropods following a riverbank, some in the river, others on its banks, slowly putting one foot foward and swinging their necks up, down, and side to side eating ferns, cycads, and horsetails. This is at least what I imagine was going on with some sauropods. They were not fast creatures by any stretch of the imagination.

As far as animals on the move, the temptation with sauropods is to want to compare them with large mammalian herbivores like elephants and giraffes, neither of which is a good model for sauropods. We must be careful not to take behavioral cues from extant large mammals as a way of interpreting dinosaur behavior, lifestyle, etc. We don't know a sauropod's physiology, we have no way to gauge metabolism, etc., so it's difficult to say how much food they would need and how fast they'd need to get it.

Plus, the trackways do show a bunch of sauropods moving together, but it tells us nothing about herding behavior necessarily. A geographic feature, like a lakeshore, may have made it necessary for a bunch of sauropods to walk through the same area without necessarily being in a herd. They may very well have herded, but we are still unclear on this. We do know many different kinds of sauropods lived together in the same areas, and how they competed with each other is still a bit of a mystery (one I am trying to unravel from one particular outlook).

In any case, sauropods are so alien that we must be careful when we interpret any aspect of their paleobiology. I'll post the neck ref, and I encourage anyone who hasn't read it to read it and see what you think from there.

Matt Bonnan

----------------- John Schneiderman -----------------

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