Modern mammals vs Dinosaurs

[Moontanman]

From the OP:

"truly mixed" is hard to define, but I think I understand what the question was about. Moontanman asks if one is genuinely better than the other one (mammals vs dinos), or is it that both actually use the same 'technology' just optimized in somewhat different way.... Or what is it that you wanted to ask by the 'truly mixed', Moon?

 

At least I would like to hear opinions about the above dilemma. Note that because modern mammals are of later design, it does not mean that they are necessarily more advanced. It might be that dinosaurs were very advanced and then... bang - the reset happened and the evolution is now starting from the middle again.

 

BTW, there is one more thing that I read throughout this thread - in what way would one non-coordinated group sustain its dominance over the other group? I don't think dinosaurs were racist pigs that were intentionally suppressing mammals. How could they prevent mammals to slowly take over? What is it that prevents today birds to step down from the trees and slowly take over the land?

 

 

after the extinction of the dinosaurs other groups did start evolving into empty niches other than mammals, crocodilians became land predators for a "short" while, things like terror birds and some mammal groups that are either no longer with us or that have been relegated to minor roles in the ecology. Used to be lots of huge land turtles as well, not just on islands.

[Acme]

What dino meat tastes like is obvious... chicken...

 

Yes there are mammals with specific diets and many that eat what ever they can get, my point is that larger animals tend to be a bit more eclectic in their eating habits but since we have no idea if this is true for dinosaurs one way or another speculation is moot.

Edit: misread >>Uhm...koalas aren't big and have a highly specialized diet. I don't see any evidence that bigger means more selective. Do you have a reference?

 

So since we don't know about dino diet, we're just going to ignore it in your scenario [and pretend it's not a factor]?

 

It's quite possible my OP was a bit vague but what I had in mind was more of a thought experiment in what would happen if a particular species of dinosaur was released into our world, minus humans, how would they fair in competition with modern mammals. I have read some assertions that dinosaurs were superior to mammals in their physiology, they are thought to have had a superior method of breathing...

If you could give a link I could read what you read and see if our understanding is equivalent. On the breathing and without a link just now -but forthcoming- they mentioned on the last Cosmos that dinos got big in part because there was a lot more oxygen in the atmosphere.

 

...

much as birds do today, hollow bones like birds for less weight and a stronger weight to strength ratio, even sauropods are now thought by some to have had these adaptations and they contributed to the size they were able to obtain.

Hollow bones on dinos? Seems contrary to my understanding of animal physiology, but I'll look something up on it unless you have a ready reference.

 

...

The life styles of modern mammals and dinosaurs were both similar and wildly different, as for the turtle comparison hiding eggs the size of golf balls is bit easier than eggs the size of footballs but it is a valid comparison but we would need to know a bit more about how things like sauropods hid or protected their eggs.

 

I think it's obvious that a large adult sauropod or large adult theropod would be invincible to modern mammal predators but i think it would not be that simple. If dinosaurs were physiologically superior to modern mammals then over long time periods they should dominate at least some ecological niches.

I suppose all-in-all anything we want to claim is good insofar as this is all speculation. Still, I've heard it said that even in Speculations we need to keep things on a sound scientific basis. And for the record, dinos taste like fish.

Edited May 11, 2014 by Acme

[Delta1212]

Uhm...koalas aren't big and have a highly specialized diet. I don't see any evidence that bigger means more selective. Do you have a reference?

 

Eclectic means the opposite of selective.

[Acme]

Eclectic means the opposite of selective.

My bad; I misread that. Nonetheless, since we don't know about dino eating habits, comparing modern large animals to them is without a basis in facts.

 

Now, do you have something more substantive to add than catching me in a grammatical error?

[Moontanman]

Uhm...koalas aren't big and have a highly specialized diet. I don't see any evidence that bigger means more selective. Do you have a reference?

 

So since we don't know about dino diet, we're just going to ignore it as a factor in your scenario?

 

 

If you could give a link I could read what you read and see if our understanding is equivalent. On the breathing and without a link just now -but forthcoming- they mentioned on the last Cosmos that dinos got big in part because there was a lot more oxygen in the atmosphere.

 

 

Hollow bones on dinos? Seems contrary to my understanding of animal physiology, but I'll look something up on it unless you have a ready reference.

 

 

I suppose all-in-all anything we want to claim is good insofar as this is all speculation. Still, I've heard it said that even in Speculations we need to keep things on a sound scientific basis. And for the record, dinos taste like fish.

 

Eclectic would mean they could eat a wide variety of plants.

 

http://en.wikipedia.org/wiki/Sauropoda

 

Air sacs[edit]

Along with other saurischian dinosaurs (such as birds and other theropods), sauropods had a system of air sacs, evidenced by indentations and hollow cavities in most of their vertebrae. Pneumatic, hollow bones are a characteristic feature of all sauropods.^[18]

The bird-like hollowing of sauropod bones was recognized early in the study of these animals, and, in fact, at least one sauropod specimen found in the 19th century (Ornithopsis) was originally misidentified as a pterosaur (a flying reptile) because of this.^[19]

 

 

Oxygen levels...

 

http://www.cnn.com/2003/TECH/science/11/03/dinosaurs.oxygen.reut/

 

Peter Ward, a University of Washington paleontologist, said Friday he thinks low oxygen and hot greenhouse conditions caused by intense volcanic activity may have caused widespread extinctions 250 million years ago, at the boundary between the Permian and Triassic periods, and about 200 million years ago, at the boundary between the Triassic and Jurassic periods.

The Permian-Triassic extinction is believed to have eradicated 90 percent of all species on Earth, including most protomammals, the immediate ancestors of true mammals.

The Triassic-Jurassic extinction killed more than half the species, including many mammals and mammal-like reptiles. But dinosaurs flourished.

Ward said he put together three pieces of the puzzle -- the extremely efficient breathing systems of birds, the finding that many dinosaurs had similar physiology, and a report that came out earlier this year showing that oxygen levels were low during the two extinctions.

"Someone told me they had heard of or seen geese flying above (Mount) Everest -- at 31,000 feet (10,000 meters)," said Ward, who presents his findings next week to a meeting of the Geological Society of America.

[Acme]

Eclectic would mean they could eat a wide variety of plants.

Did you not read my acknowledgement of this in the previous post, or did you just want to take another poke at me after Delta's?

 

 

 

Oxygen levels...

 

http://www.cnn.com/2003/TECH/science/11/03/dinosaurs.oxygen.reut/

I'll read that over and see if I can root out what I heard/misheard on the Cosmos program.

 

But still, these are side issues that I was asking you for clarification on and they don't have any bearing on the lack of evidence for dino diets. You said

 

we have no idea if sauropods were specialists or not. We can see that a great many large herbivourus mammals eat highly varied diets, I would think it justified to assume dinosaurs were just as adaptable.

Since your whole premise in this thread is to pit survivability of today's mammals against dinosaurs and this because of how different they are, it seems rather unjustified to make the assumption you do. Basically then, anything anyone wants to assume is as good as the next person's assumption. Fine; mammals would win because I think so.

 

PS Those sauropod hollow bones were in the vertebrae according to your link, not the limbs that support the weight as you implied when you said :

...hollow bones like birds for less weight and a stronger weight to strength ratio, even sauropods are now thought by some to have had these adaptations and they contributed to the size they were able to obtain. ...

Edited May 12, 2014 by Acme

[Moontanman]

Did you not read my acknowledgement of this in the previous post, or did you just want to take another poke at me after Delta's?

No we must have cross posted.

 

 

 

I'll read that over and see if I can root out what I heard/misheard on the Cosmos program.

 

But still, these are side issues that I was asking you for clarification on and they don't have any bearing on the lack of evidence for dino diets. You said

What side issues?

 

 

 

Since your whole premise in this thread is to pit survivability of today's mammals against dinosaurs and this because of how different they are, it seems rather unjustified to make the assumption you do. Basically then, anything anyone wants to assume is as good as the next person's assumption. Fine; mammals would win because I think so.

Not entirely accurate, I am thinking about how well they would or would not compete with each other, I used the idea that dinosaurs were indeed superior to mammals.

 

Dinosaurs took over dominance from early mammals due to low oxygen levels and the superiority of dinosaur breathing, one of the links I provided asserts this.

 

There were large predatory animals way before dinosaurs, anapsids were common large animals that are now only survived by turtles, the early mammal like reptiles like dimetrodon and many other para reptiles could not compete with the dinosaurs who lived through the "great dying" of the Permian due to their superior breathing apparatus among other things. Dinosaurs didn't evolve until around 230 million years ago, they took over from the other para reptiles like the mammal like reptiles after the great dying. The first dinosaurs were small insignificant creatures but they inherited the world and dominated it for 150 million years...

 

Hollow bones and air sacs also contributed to the gigantism of dinosaurs, crocodiles which survived the KT boundary and are also archosaurs do not share the breathing apparatus and hollow bones of dinosaurs and could not compete with the evolving mammals for land niches.

 

The fixation on whether they could or could not eat modern vegetation has little bearing since modern vegetation had taken over the planet many millions of years before the dinosaurs became extinct so they most certainly could eat modern vegetation..

Edited May 12, 2014 by Moontanman

[Acme]

Fine. Obviously you are right and I am wrong. Can't win them all.

[Moontanman]

Fine. Obviously you are right and I am wrong. Can't win them all.

So since i can at least provide some evidence of my stance and you can't you'll just take your ball and go home?

 

I suggested you give me some idea of the side issues, I think I addressed the major parts, I am not asserting anything but facts and speculating from those facts, so far all you seem to want to do is talk about sauropods eating what ever...

[Acme]

So since i can at least provide some evidence of my stance and you can't you'll just take your ball and go home?

Yup.

[SamBridge]

This is simply not true

Well, except that it kind of is. These large dinosaurs we're talking about here aren't the slow ones you see in Jurassic Park (which got anatomical aspects of dinosaurs wrong), those Brontosaurus were fast, which takes enormous amounts of energy. Dinosaurs were not "hot blooded" as you think mammals are. They had a higher temperature at their size not due to being like mammals, but due to their Giganothermy. Dinosaurs as you might know are descended directly from reptiles, which are cold blooded, but were able to grow so big and keep a high Metabolism, not because they were hot-blooded as modern mammals, but because they were "luke-warm" blooded, and their body temperature as adults was regulated not by the enzymatic reactions of mammals, but by their sheer size resulting from their Cascade Evolution, achievable only if the dinosaurs were able to initially take in energy from their environment just as reptiles did.

[Moontanman]

Well, except that it kind of is. These large dinosaurs we're talking about here aren't the slow ones you see in Jurassic Park (which got anatomical aspects of dinosaurs wrong), those Brontosaurus were fast, which takes enormous amounts of energy. Dinosaurs were not "hot blooded" as you think mammals are. They had a higher temperature at their size not due to being like mammals, but due to their Giganothermy. Dinosaurs as you might know are descended directly from reptiles, which are cold blooded, but were able to grow so big and keep a high Metabolism, not because they were hot-blooded as modern mammals, but because they were "luke-warm" blooded, and their body temperature as adults was regulated not by the enzymatic reactions of mammals, but by their sheer size resulting from their Cascade Evolution, achievable only if the dinosaurs were able to initially take in energy from their environment just as reptiles did.

 

 

Sam, you do realize that dinosaurs were as removed from reptiles as are mammals? Both evolved from "reptiles" and many mammals are not exactly "hot Blooded" I do see your point, it is thought that dinosaurs may have been more diverse as far as body temps are concerned than we commonly think of as mammals. "Reptile" is no longer considered as an accurate descriptive term. Possibly if we want to get serious in this discussion we should be saying anapsids, diapsids and synapsids all of these groups evolved from para reptiles as well as many animals that simply didn't make the "cut"

 

I am well aware that Jurassic park was a Hollywood fantasy, I am basing my assertions on paleontology not movies. Dinosaurs were as to birds as bats are to mammals both evolved from para "reptiles". Most of them had feathers, even sauropods are thought to have had fuzzy feathers similar to baby chickens by some paleontologists, probably not as adult but the young.

 

The hollow neck bones and air sacs are indicative of bird like breathing and a high metabolism, young sauropods were probably more endothermic than gigantothermic and even today there are endothermic "reptiles" even fish, endothermy is not an off on thing and even insects have some limited endotherms.

 

Theropods were almost certainly endotherms much like birds and also had the signature air sacs hollow bones and more efficient breathing than mammals.

 

Sauropods evolved from far more bird like dinosaurs which survived the great dying because of both endothermy and other bird like features.

 

Also dinosaurs lived inside the arctic and anarctic circles which also suggests they were endotherms.

 

Still no such thing as a brontosaurus, apatosaurus is the correct name.

Sam, I started out intending to defend mammals now i find myself on the other side, typical when you start out with a presupposition and look into it deeper.

[dimreepr]

I think maybe we should focus the discussion on animals that are similar in size and approximate dietary requirements. An animal such as the larger of the sauropods are unlikely to compete directly with cattle (other than accidentally treading on the odd cow/sheep), also they couldn’t possibly have modern predators, even insects.

I’ve been pondering the likely fate of an animal of that size in our modern world; it strikes me that, whilst I have no reason think they couldn’t survive on flora of this era, they would need a vast amount of what they could eat, which clearly existed in their era but not very likely in ours and coupled with a need to be near enough a large amount of water would severely limit their chances.

Edited May 12, 2014 by dimreepr

[Moontanman]

I think maybe we should focus the discussion on animals that are similar in size and approximate dietary requirements. An animal such as the larger of the sauropods are unlikely to compete directly with cattle (other than accidentally treading on the odd cow/sheep), also they couldn’t possibly have modern predators, even insects.

I’ve been pondering the likely fate of an animal of that size in our modern world; it strikes me that, whilst I have no reason think they couldn’t survive on flora of this era, they would need a vast amount of what they could eat, which clearly existed in their era but not very likely in ours and coupled with a need to be near enough a large amount of water would severely limit their chances.

 

 

I'm not sure what you mean, sources of water? All large animals would need that mammals included, I don't see plants being anymore lush then than now, is there reason to think so?

[Greg H.]

I think maybe we should focus the discussion on animals that are similar in size and approximate dietary requirements. An animal such as the larger of the sauropods are unlikely to compete directly with cattle (other than accidentally treading on the odd cow/sheep), also they couldn’t possibly have modern predators, even insects.

Well, let's take Compsognathus logipes then as a starting place, as compared to a Striped Polecat, Ictonyx striatus, an African mammal of roughly the same size.

 

Both eat small vertebrates, C. logipes documented as eating small vertabrtate lizards, while I. striatus is known to eat small mammals, birds, snakes, and insects. There's no real reason to suspect that C. logipes couldn't adapt to catch other small, agile creatures such as rats and mice, since they were already adept at catching small, agile lizards. I suspect that the "winner" in this contest would come down to something more subtle, and quite possible environmental. It is possible that the dinosaur would win in some environments and the weasel would win in others, based on conditions present at the time, and the ability to capture food and avoid larger predators.

[Moontanman]

Well, let's take Compsognathus logipes then as a starting place, as compared to a Striped Polecat, Ictonyx striatus, an African mammal of roughly the same size.

 

Both eat small vertebrates, C. logipes documented as eating small vertabrtate lizards, while I. striatus is known to eat small mammals, birds, snakes, and insects. There's no real reason to suspect that C. logipes couldn't adapt to catch other small, agile creatures such as rats and mice, since they were already adept at catching small, agile lizards. I suspect that the "winner" in this contest would come down to something more subtle, and quite possible environmental. It is possible that the dinosaur would win in some environments and the weasel would win in others, based on conditions present at the time, and the ability to capture food and avoid larger predators.

 

I agree, the environment wasn't as different during the time of the dinosaurs as many think. An animal that eats small animals would do so even if the small animals were different than they are used to.

 

I am leaning toward disease being a significant factor as well...

 

It's important to note that many if not all small theropods were covered in feathers, this would seem to indicate they could live in temperate environments as well. Makes the idea of them living in our time a bit more realistic.

[dimreepr]

I'm not sure what you mean, sources of water? All large animals would need that mammals included, I don't see plants being anymore lush then than now, is there reason to think so?

 

"they would need a vast amount of what they could eat" That's the important phrase in my previous post. So with that in mind:

 

In a perfect world an elephant will eat 150lbs of food a day, in an imperfect world they can eat over 770lbs and consume as much as 200 litres of water a day; so if we conservatively estimate the difference in weight of 4/5 times, that would be a vast amount of food and water to find each and every day if conditions aren’t optimal and very substantial amount if they are, so where on the planet would they have to land to merely survive let alone thrive?

 

 

Edit- Not forgetting a small herd would be needed to maintain a population and thus, sustainable.

Edited May 12, 2014 by dimreepr

[Moontanman]

 

"they would need a vast amount of what they could eat" That's the important phrase in my previous post. So with that in mind:

 

In a perfect world an elephant will eat 150lbs of food a day, in an imperfect world they can eat over 770lbs and consume as much as 200 litres of water a day; so if we conservatively estimate the difference in weight of 4/5 times, that would be a vast amount of food and water to find each and every day if conditions aren’t optimal and very substantial amount if they are, so where on the planet would they have to land to merely survive let alone thrive?

 

 

Edit- Not forgetting a small herd would be needed to maintain a population and thus, sustainable.

 

 

Still, why would you say they couldn't find enough food, ever been to the tropics? Even where I live in the subtropics vegetation is quite lush. Water is close as the nearest river, just like other large animals they would live near a source of water, lush vegetation is generally near a source of water...

As Sam suggested if they are gigantotherms they would eat and drink less than their size would suggest...

[dimreepr]

 

 

Still, why would you say they couldn't find enough food, ever been to the tropics? Even where I live in the subtropics vegetation is quite lush. Water is close as the nearest river, just like other large animals they would live near a source of water, lush vegetation is generally near a source of water...

 

It was just a ponder and I wasn’t suggesting they couldn’t find a suitable area; just that it could be difficult. Plants are part of the predator/prey arms race which means some plants have developed resistance to grazing through various means, poisons included.

 

As Sam suggested if they are gigantotherms they would eat and drink less than their size would suggest...

 

In fairness we have no way of knowing how efficient their digestive systems were, it’s therefore reasonable to use elephants as a rough guide.

[dimreepr]

Well, let's take Compsognathus logipes then as a starting place, as compared to a Striped Polecat, Ictonyx striatus, an African mammal of roughly the same size.

 

Both eat small vertebrates, C. logipes documented as eating small vertabrtate lizards, while I. striatus is known to eat small mammals, birds, snakes, and insects. There's no real reason to suspect that C. logipes couldn't adapt to catch other small, agile creatures such as rats and mice, since they were already adept at catching small, agile lizards. I suspect that the "winner" in this contest would come down to something more subtle, and quite possible environmental. It is possible that the dinosaur would win in some environments and the weasel would win in others, based on conditions present at the time, and the ability to capture food and avoid larger predators.

 

A very nice example of direct dinosaur/mammal competitors.

 

“avoid larger preditors”

Maybe one way the mammals would have the upper hand in this scenario; they would recognise the predators, the dinosaurs would have no idea what to fear.

 

I think kronosaurus would make an interesting foe for the killer whale, even more interesting if they too travelled in family units.