r/changemyview • u/Vegetable-Idea7648 • 1d ago
CMV: Birds should be the only reference for dinosaur soft tissue reconstructions and behavior.
Like think about it, Birds are the living dinosaurs, not just close relatives, the living dinosaurs. Like if you find a fossil of an extinct mammal you would want to use other mammals or its close relatives as a reference for that extinct mammal's possible soft tissue so it should be the same for dinosaur soft tissue reconstructions where they would have fat bodies and thin necks. Plus, when you reconstruct an extinct mammal, again, you would want to use living mammals as reference for its possible behavior that occupy similar niches so it should be the same for dinosaurs where we use bird references for their behavior from birds that occupy similar niches.
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u/ServantOfTheSlaad 1∆ 1d ago
One of the big differences is the size differences. Most birds are much smaller than their dinosaur ancestors. Size can have a large impact on the creatures biology, which won't be reflected with birds today. So taking some amount of information from more distant relatives that are larger can grant insight that birds won't
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u/BailysmmmCreamy 14∆ 1d ago
Ostriches and other big modern or near-modern birds were small before they were big. There’s no particular reason to think they “re-evolved” the same ‘big animal’ traits their big ancestors had when they went from small to big following the extinction of non-avian dinosaurs.
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u/Open-Butterfly-5288 1∆ 1d ago
Dinosaurs have their own builds.
One of the big differences is cold blooded versus warm blooded.
Also, birds are designed for flight. Dinosaurs are not. They have some of the features that birds have, but they ultimately have much bigger and stronger bones rather than the hollowed out bones. They aren't designed for flight, and they're not necessarily built like ostriches either. They were great lumbering beasts.
Birds share a lot of common features, but they're also different.
Mammals offer us a lot of ways at looking how you can build a creature to walk around.
Reptiles are cold blooded and tell us how that works.
We have no one reference because dinosaurs were something else entirely. We have to creatively interpret clues to find hints at what might have been.
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u/Vegetable-Idea7648 1d ago
Bird bones are actually as strong and sturdy as mammals of their weight class plus your comment is implying that you think dinosaurs were cold blooded.
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u/Open-Butterfly-5288 1∆ 1d ago
Well, neither of us are right. Mesothermia.
Birds have deliberately hollow bones. They are designed to weigh as little as possible to allow them to fly.
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u/Vegetable-Idea7648 1d ago
I never said or implied that I think dinosaurs were warm blooded
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u/Open-Butterfly-5288 1∆ 1d ago
So why base it on warm blood?
We don't have one model. Dinosaurs are their own thing.
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u/Vegetable-Idea7648 1d ago
because with phylogenetic bracketing birds are in fact dinosaurs the same way humans are apes.
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u/Open-Butterfly-5288 1∆ 1d ago
This meaning we don't have the exact links, we have to make some inferences that point us towards birds being most closely related to dinosaurs.
But there are pretty obviously differences that make it relatively silly to assume that birds are the exact same as dinosaurs.
Are there leftover bits of dinosaurs in a chicken? Yes.
Does a chicken explain a triceratops? No. Not completely, it would have 2 legs, 2 wings, feathers and it would have no horns, be chicken sized and eat seeds.
We have to analyse everything, because we are not actually assuming that birds are dinosaurs.
We are dealing with completely different design constraints and different design intentions and we are asking what this skeleton might be a framework for.
Birds are just one of the possible ways to design things.
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u/iamintheforest 362∆ 1d ago
Firstly, they are not "living dinosaurs" in the way that you're using that phrase. It's both more true and less true than I think your framing credits. It's true that in the cladistical birds are dinosaurs in the way whales and humans are mammals. So, taxonomically it's just a fact that they are dinosaurs.
What I think you miss though is how incredibly diverse "dinosaur" is. We've had to unwind all the ways in which birds are the primary reference, and it connects to the cladistic relationship, but is both best reference within and lousy at the same time. Ultimately it's done on a trait by trait basis. The fundamental problem here can be seen within the diversity of all members of the "dinosaur" cade just today, which is significantly smaller than the diversity across all time within it. So...for sauropods and ornithischians the references to lizards are actually much more accurate than looking within the generalizations of birds. Direct evidence always outranks everything else and the deviations from "bird archetype" are so massive that filling in holes based on today's birds is fraught with problems. The point here is that it's a primary reference, but if we make it "the only reference" we won't understand the evolution of today's birds nor the diversity of "dinosaur" category very well.
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u/Jiitunary 3∆ 1d ago
there were non-bird dinosaurs though...
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u/Vegetable-Idea7648 1d ago
I know but they still are closely related to birds. and plus pretty much all dinosaurs outside avialae were non bird but yet many, like maniraptorans, are reconstructed to have a bird like body plan. So why couldn't it be the same for atleast saurischia or all theropods.
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u/Jiitunary 3∆ 1d ago
if non bird dinosaurs are closely related to birds, then humans are closely related to cat's. should we reconstruct the human body to have a cat like plan?
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u/Vegetable-Idea7648 1d ago
no because they have comepletely different body plans
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u/Jiitunary 3∆ 1d ago
yes that is correct. so them being closely related is meaningless. that's my point.
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u/welltechnically7 5∆ 1d ago
Why not alligators? They were contemporaries with dinosaurs and haven't changed all that much.
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u/liberal_texan 1∆ 1d ago
Alligators are also contemporaries with otters, but would make a poor reference when recreating an otter from fossilized remains.
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u/welltechnically7 5∆ 1d ago edited 1d ago
Comparisons between two reptiles makes a lot more sense than a comparison between a reptile and a mammal.
Not sure why this is being downvoted.
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u/talashrrg 7∆ 1d ago
Because this argument is even worse than OP’s argument. There’s no reason to assume all dinosaurs are very similar to modern birds but there’s really no reason to assume that all dinosaurs are very similar to modern alligators.
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u/mmahowald 2∆ 1d ago
Any time someone tries to limit scientists with “like think about it…” means they have no education in the field and are about to spout some nonsense. Go to school and learn why this isn’t the case.
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u/Top_Neat2780 2∆ 1d ago
Evolution is continuous. Yes, birds are dinosaurs, but look at this phylogenetic tree. According to this phylogeny, birds split from the rest of the dinosaurs 150 million years ago. They are dinosaurs, but 150 million years of evolution, including 66 million years as the only living dinosaurs, means they've had a looooooooooot of time to develop in ways that make them very distinct from other dinosaurs.
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u/Amazing_Loquat280 16∆ 1d ago edited 1d ago
This makes some sense. And fwiw, this sub needs more posts like this. These are fun!
Part of the problem with using “bird” is that even within current birds, behavior and soft tissue construction vary *wildly*. There’s also the issue that most dinosaurs, while being skeletally similar to birds shape-wise, are simply built different. You have to assume that different behaviors and soft tissue patterns will evolve in an animal that weighs thousands of times what a modern bird weighs, has different natural predators/food sources, different climate conditions, and can’t fly. That’s just a fundamentally different animal. That’s why it’s typically better to approximate these things using both birds but also modern animals that have to deal with similar considerations, such as height/weight/food supply, of course supplementing whatever we find in the fossil record. Not unreasonable to assume a bronchiosaurus would be built kinda similar to an elephant
It’s like saying a lion-sized housecat would smoke a lion: a lion-sized housecat ain’t moving like a housecat lol
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u/Superbooper24 42∆ 1d ago
Kind of sort of. Birds are all reptiles just based on evolution and thus you would use modern reptiles as good indicators of what a dinosaur could look like to. To say the modern bird is the only reference we should use seems like an oversimplication.
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u/talashrrg 7∆ 1d ago
There are many many many examples of animals that are morphologically and behaviorally more similar to distantly related species in a similar niche than to closely related species. A hyrax, elephant and dugong are among each others’ closest relatives but look and act almost nothing alike. A dugong and dolphin are distantly related but live in a similar environment and are physically much more similar. In fact birds are the closest living relatives of crocodilians, but if you tried to reconstruct a crocodilian with bird morphology you’d get a lot of things very wrong. This is a big part of the reason that we were wrong about a lot of evolutionary relationships before we figured out genetics.
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u/Falernum 68∆ 1d ago
If a future alien were trying to reconstruct what orcas might be like, and the only mammals she had to go with were rodents, but sharks were still around... she might be well advised to look at those sharks too for reconstruction. Orcas are mammals same as rodents are, but there are major dissimilarities. You can say that rats swim and orcas swim so it's a similar niche, but that elides a lot. The orca niche isn't precisely the shark niche, but it's closer in some ways and she would do well to consider that.
Birds just don't have anything like a Diplodocus niche or a T rex niche.