1/15 Ceratosaurus on Nest

[Seijun]

Himmapaan: I dunno a flock of birds all seem to sit relatively the same way when I see them like with nesting grounds and stuff. (Their heads can be all over the place but their bodies tend to be pretty uniform).

Seijun: Birds don't really have flexible spines. Many dinosaurs also had ossified tendons running down the length of their spines making them stiff. And different sorts of animals lay in the mud all the time.

That may be true, but what started this entire conversation was the fact that birds can and do lay in odd positions sometimes, and don't always lay sitting strait with legs tucked perfectly beneath them.

And different sorts of animals lay in the mud all the time.

True again, but not not all, and maybe not the majority. The point being, our fossil tracks of animals resting is probably not all encompassing. People are often very quick to make broad judgments on dino behavior based on only a few fossil finds, or even a single one.

This whole things brings up another peeve of mine. I think people try to compare birds to dinosaurs too closely on occasion, such as comparing sauropods or hadrosaurs to birds. I understand that birds are the closest living relatives to "dinosaurs" and the best thing we have for comparison, but they did only evolve off of the smaller theropod dinosaurs, and there are literally millions of years in between modern birds and ancient dinosaurs. It's like comparing modern apes to plesiadapis or notharctus! Comparisons certainly can be made, and should be made, but they should not be treated as having been the same behaviorally.

[Griffin]

Please don't lump me into the people who peeve you. I'm on my 5th year studying animal science and evolution at a university and I have been working with zoo animals for 10 years I work to hard to deserve that sort of classification myself. (Don't mean to toot my own horn but one of MY peeves is being underestimated) OF COURSE I know a deinonychus is much much closer to a bird than say a parasaurolophus but the fact remains still that when it comes to modern models birds (and crocs) is a good starting point. When it comes to guessing how dinosaurs behaved or whatever we cant deduct with hard evidence alone, its best to look at modern relatives for possible guesses.

When a bird lays on its side like in your photo, the whole body is off to the side because the spine can't twist. The lufengo pic has the majority of the torso laying straight against the ground but the pelvis is twisted off to the side with the legs splayed out that way. I really don't think, assuming the spine was pretty stiff (in many dinosaurs, not just bird-like theropods, it is) this doesn't seem plausible.

I'm really not one of those people who goes around killing imaginations or anything. But again what needs to be done is a study on whether or not a dino's bones could physically allow it to do something like that. My guess as of now is no.

[Seijun]

Oh, my comment about peeves was not directed at you or anyone else in particular! Its more like a peeve at what seems to be a prevailing thought pattern among dino folks in general, but not an on purpose thought pattern. It just happens Birds ARE the closest thing we have to dinosaurs and I completely agree with you, that they are the best starting point when theorizing about dinosaur behavior. But, it is important to not constrain theories on dinosaur behavior to only what can be observed in modern birds.

The lufengo in the foreground would be doubtful if lufengo spines are like bird spines. The ones in the background appear to be laying more like the chickens. The pose of the lufengos in the background does look more natural.

[Himmapaan]

Aug 27, 2011 13:44:34 GMT Griffin said:

Himmapaan: I dunno a flock of birds all seem to sit relatively the same way when I see them like with nesting grounds and stuff. (Their heads can be all over the place but their bodies tend to be pretty uniform).

They do. Which is why I tend towards quadrupeds in my theorising. I agree it seems less likely for theropods and other bipedal dinosaurs. I do take your point about limited flexibility in the spine, however.

[Griffin]

Aug 28, 2011 7:14:54 GMT Seijun said:

Oh, my comment about peeves was not directed at you or anyone else in particular! Its more like a peeve at what seems to be a prevailing thought pattern among dino folks in general, but not an on purpose thought pattern. It just happens Birds ARE the closest thing we have to dinosaurs and I completely agree with you, that they are the best starting point when theorizing about dinosaur behavior. But, it is important to not constrain theories on dinosaur behavior to only what can be observed in modern birds.

The lufengo in the foreground would be doubtful if lufengo spines are like bird spines. The ones in the background appear to be laying more like the chickens. The pose of the lufengos in the background does look more natural.

Believe whatever you want I'm just telling you what I know lol

[paleoferroequine]

Oh, I'm gonna stick my nose in this. ;D Not that I know anything. When a mammal lays down like the front Lufengosaurs, they get up by pushing first with the front legs to an upright position. Then the back legs are pulled under and then push the rear torso up. When in the position like the rear Lufengosaurs, they twist the torso to get the front upright and repeat the above. If a dinosaur was laying down completely, it would have to be able to twist the torso first to get the front part vertical. If the spine was rigid, it would have great difficulty getting up, which I think might rule out laying down on their sides. So the back Lufengosaurs most likely would have to attempt to do that. I've seen chickens lay on their sides, but they do have some problem getting up gracefully, the kind of roll and flip, but they are light weight. Also small birds getting a dust bath sometimes end up on their sides or even backs, but they don't weigh much and can roll easily. And I've seen a parakeet sleep on its back(only one) and it got up by rolling. Of course, this all brings up the point if the Lufengosaurus does fall down, what happens? I guess it flails about and rolls till it gets on it's belly and then can push up? Call Life Alert: "I've fallen and I can't get up!"
I saw a YouTube video with an elephant trying to get up from a laying flat position, even it had a lot of trouble. It flailed about and tried to roll, but if it hadn't been able to twist the front half, it wouldn't have been able to get up at all. But, has there been a study to see if the spine and torso in dinosaurs were rigid enough to preclude laying on their sides?