Post APSmznQoci1d7i2AJk by Ivan22@sauropods.win
(DIR) More posts by Ivan22@sauropods.win
(DIR) Post #APSar2VjzRsDpqOaw4 by Ivan22@sauropods.win
2022-11-10T08:18:20Z
0 likes, 1 repeats
A #sauropod for sauropods.win. The giant Late #Jurassic diplodocid Supersaurus - one of the most spectacular sauropods - rears in a tripodal position to feed from the high branches of a conifer tree. The small ornithischian Nanosaurus looks on in the foreground. #dinosaurs #palaeoart
(DIR) Post #APSmzm31lfP2pdtebI by mike@sauropods.win
2022-11-10T13:01:30Z
0 likes, 0 repeats
@Ivan22 I am all for rearing sauropods — but why is this one doing it, when there is so much foliage lower down on the same tree?
(DIR) Post #APSmzmV25XnwEV01Fg by Ivan22@sauropods.win
2022-11-10T13:19:52Z
0 likes, 0 repeats
@mike That's a fair point, it could have started lower. I suppose I could argue that animals don't reliably do the lowest effort thing. Cats will hunt given the chance even if they have access to unlimited food at home.
(DIR) Post #APSmzmySK9L9hklW76 by llewelly@sauropods.win
2022-11-10T13:33:24Z
0 likes, 0 repeats
@Ivan22 @mike in the case of cats surplus hunting, there's an explanation: though they are solitary hunters, they live in groups, and bring home prey for the group, and surplus hunting improves survival of the group.Now I'm imagining surplus feeding by sauropods; they eat tons, then they bring home the surplus from the group, presumably regurgitating it. An interesting idea, but it seems unlikely. Could be an answer to the age-old question "what do baby sauropods eat?", though.
(DIR) Post #APSmznQoci1d7i2AJk by Ivan22@sauropods.win
2022-11-10T13:47:19Z
0 likes, 0 repeats
@llewelly @mike It's not quite as simple as that though. Many predators will sometimes kill far in excess of their food needs, and this is seen as instinctive behaviour. The same applies to locomotion; eagles spend far more time on the wing than necessary to meet their food and travel needs. I think we need to make allowance for the fact that a certain amount of the energy animals expend is explained by the desire for play, or at least stimulation.
(DIR) Post #APSmzo4AGPV75kRaeO by mike@sauropods.win
2022-11-10T13:53:08Z
0 likes, 0 repeats
@Ivan22 @llewelly As a principle, I agree. But I'm not sure how often we see that in very heavy animals for which rearing is both energetically expensive and potentially dangerous. I believe that elephants in the wild rear only very rarely — can anyone confirm or dispute? CC @TetZoo
(DIR) Post #APSmzoVobbcQTVNfkW by Ivan22@sauropods.win
2022-11-10T14:05:01Z
0 likes, 0 repeats
@mike @llewelly Yeah I think that's fair. Though I do think diplodocids are much better suited to rearing than elephants, what with a centre of mass just in front of the hips and the opportunity to use the tail as a third support.
(DIR) Post #APSmzp72NDOQKwnOlc by mike@sauropods.win
2022-11-10T14:20:40Z
0 likes, 0 repeats
@Ivan22 @llewelly In terms of shape, I agree. In terms of sheer body mass, not so much.
(DIR) Post #APSmzpgqE6267zXzZg by john@sauropods.win
2022-11-10T14:25:48Z
0 likes, 0 repeats
@mike @Ivan22 @llewelly But of course it's much easier for them to get into the position where gravity will make them rear. Add to that an elephant has to be more careful to get the balance exactly right or they could fall over backwards!
(DIR) Post #APSnW21ltIlNeugtJQ by Ivan22@sauropods.win
2022-11-10T14:31:57Z
0 likes, 0 repeats
@john @mike @llewelly Yeah, that's what I was thinking. But as Mike says they are huge animals compared to an elephant. I suppose we can never really know how different things would or wouldn't be for a 30 tonne land animal compared to the little munchkins we have now.
(DIR) Post #APSoLQJfLW8tl1ZAX2 by john@sauropods.win
2022-11-10T14:41:15Z
0 likes, 1 repeats
@Ivan22 @mike @llewelly Yeah, but I think we can guess! Diplodocids have such huge advantages over elephants when it comes to rearing:- Centre of balance really close to fulcrum- More robust hindlimbs- A tail to stick the landing- The ability to lock their knee straight while rearing (elephants have to maintain a bent knee stance)I actually think diplodocids were specialised rear-ers, which is why they look the way they do.
(DIR) Post #APSofhKrmIzSKknNQ0 by mike@sauropods.win
2022-11-10T14:44:53Z
0 likes, 0 repeats
@john @Ivan22 @llewelly See also:* "A bipedal Diplodocus? It's not as crazy as it sounds" by yours truly for the BBC: http://www.miketaylor.org.uk/dino/pubs/popular/Taylor2013-WWD-06-bipedal.pdf* "SO close" by Matt Wedel at SV-POW!: https://svpow.com/2014/08/21/so-close/* Addendum to SV-POW!’s “SO close” by @palaeo3d (who has done the real work): https://dinosaurpalaeo.wordpress.com/2014/08/25/addendum-to-sv-pows-so-close/
(DIR) Post #APSpGfjah6dM59zUAK by Ivan22@sauropods.win
2022-11-10T14:51:37Z
0 likes, 0 repeats
@john @mike @llewelly Yeah I think along the same lines with diplodocids. Especially with the sled runner shaped chevrons under the relevant section of the tail, which fits so perfectly with the idea of frequently adopting a tripodal stance. Is there any current thinking about the proposed problem of blood pressure when the neck is vertical? With the currently preferred elevated neck posture, the vertical displacement between head and heart is almost as great on four legs as when rearing.
(DIR) Post #APSqEdaFoqKsmsDWng by mike@sauropods.win
2022-11-10T14:53:15Z
0 likes, 0 repeats
@Ivan22 The blood-pressure problem has never really been seriously addressed by us on the raised-neck side. There are a ton of papers by Roger Seymour arguing that for this reason sauropods could NOT raise their necks, let alone rear. They are worthy of more attention that we have given them. (There's just so much else that needs doing!)
(DIR) Post #APSqEe55yB0QKWe9s8 by john@sauropods.win
2022-11-10T15:02:25Z
0 likes, 0 repeats
@mike @Ivan22 I feel like this is something sauropods solved doing something weird that we might never know about. Air sacs will be involved is my bet.
(DIR) Post #APSqfZV174QnwEbvUW by mike@sauropods.win
2022-11-10T15:07:16Z
0 likes, 0 repeats
@john @Ivan22 See the screencap from an in-prep paper on the AMNH's rearing Barosaurus mount. There have been PLENTY of suggestions for weird innovations in sauropod circulation.
(DIR) Post #APStFaP1QpWL4b6j1k by Ivan22@sauropods.win
2022-11-10T15:19:28Z
0 likes, 0 repeats
@mike @john I love the multiple hearts idea but that is a WILD speculation - seems about as far from parsimonious as possible. Seems like an insanely complex solution to a simple (albeit large) problem
(DIR) Post #APStFanpwZN0JYiXho by mike@sauropods.win
2022-11-10T15:25:59Z
0 likes, 0 repeats
@Ivan22 @john The problem about the "simple" problem is that the energy required to pump blood up a column doesn't just grow linearly with the height of the column. It's worse than that, because as the heart becomes bigger (to generate more power), so more energy is required to deform the walls of the heart itself, as well as to do the actual pumping.
(DIR) Post #APStFbFqGRltiPouMC by john@sauropods.win
2022-11-10T15:36:12Z
0 likes, 0 repeats
@mike @Ivan22 Column's a problem huh? ...by jove I've got it!
(DIR) Post #APStVXPaJscKQjydiC by mike@sauropods.win
2022-11-10T15:39:03Z
0 likes, 0 repeats
@john @Ivan22 Paging bird tracheae!
(DIR) Post #APSwWD83W1fDg0n4GO by mike@sauropods.win
2022-11-10T13:39:06Z
0 likes, 1 repeats
@llewelly @Ivan22 As you are referring to the old Nourishing Vomit Of Eucamerotus hypothesis. And old friend to @TetZoo and me.
(DIR) Post #APSxgGHOkwLmIYW6V6 by llewelly@sauropods.win
2022-11-10T16:25:43Z
0 likes, 0 repeats
@john @mike @Ivan22 A thing I often wonder about on this topic: LSOs. Birds have Lumbar-Sacral Organs, which are thought to function as accelerometers or balance organs of some kind, in their lumbar and sacral vertebrae. This is what enables a chicken with its head cut off to keep its balance while running.Did sauropods have them? Do crocs have them?