Dinosaurs May Have Been Warm-Blooded

PxT writes: "According to this AP story, the remains of a 66 million-year-old dinosaur suggest that the extinct creatures were warmblooded - not coldblooded as once believed - and capable of the swift and sustained motion typical of modern birds and mammals. A whole site dedicated to the discovery of this specimen is here."

Comments

Ha!

[Lagos]

As a closest paleontologist, I feel a little vindicated. As someone else pointed out correctly, this debate has been going on since the 70s, when John Ostrom unearthed Deinonychus, the speedy dromaeosaur that was the inspiration for Michael Cricton's Jurassic Park (Calling them Velociraptors is Gregory Paul's fault.) One could argue that the debate goes further back, all the way to Darwin's (the man, not the OS) friend Thomas Henry Huxley (the geologist, not the author [though he was the author's ancestor]), who first argued that Compsognathus Longipes could be an ancestor of modern birds. These are the little "Compy" dinosaurs that bite the girl at the beginning of Lost World.

But of course events in recent years have added to the debate. John Horner found evidence of dinosaur nesting and care, for example. Bob Bakker continued the crusade, and discoveries in China such as Sinosauropteryx or Caudipteryx zoui have more or less closed the debate, although purist Paleontologists like Larry Martin have yet to concede with grace.

The point is that this is old news, and nothing that everyone wouldn't know without moderate education. The media is obviously not properly educated in this, or anything.

What is interesting about this discovery is that it deals with a plant eater rather than a Theropod. Most of the evidence for warm-blooded in dinosaurs that I have read largely deals with the nature of the predators, whose active lifestyles lend themselves to a endothermic biology.

If an orinithiscian like Thescelosaurus is warm-blooded, it lends a lot of credit to the argument that Theropods were warm-blooded, as the groups share a common ancestor.

the reason this is important

[lubricated]

I see alot of people saying " no shit". But this is important. For the first time scientists have found a dinosaur heart. This heart is a four chambered heart. Which means it would allow for a high metabolism that warm blooded animals require. This is the first substinative evidance that dinosaurs were warm blooded before now scientists were only speculating that the dinosaurs were warm blooded

Something to keep in mind.

[Bowie J. Poag]

This article isn't trying to assert that all dinosaurs were either cold-blooded or they were all warm-blooded. They were almost certainly members of both groups.

If you look at modern reptiles, the larger species tend lead more or less sedentary lives, whereas the smaller ones tend to be far more active. They are specialized to handle whatever environment they exist within..Larger herbivorous dinosaurs (hey look, I used my big word for the day..herbivorous!) would generally have no need for long, sustained periods of activity. They dont hunt. Meanwhile, other species depend on hunting and scavanging for a living, and perhaps could benefit from the advantage of being warm-blooded.

Also, when talking about a period of time as large as this, there were no doubt adaptations from cold to warm-blooded. After the mass extinction that signaled the beginning of the Cretaceous era, generally the only forms of life which thrived were those which were small, warm-blooded, and smart. :)

Anyway, all that science mumbo-jumbo is beside yje point. If I were a dinosaur, I would prefer being warm-blooded to escape predation. Its kinda hard to hide behind a palm tree when you're 5 stories tall, and as wide as a house. :)


Bowie J. Poag
Project Founder, PROPAGANDA For Linux (http://metalab.unc.edu/propaganda)

Media Is Stupid

[waldoj]

I've been amazed that the reaction that most of the media has taken to this story. My local news station presented the story as if the very concept of warm-blooded dinosaurs was a previously unconsidered option.

(Yes, I'm fully aware that this doesn't settle the question and, yes, I know that there was the warm-blooded backlash a few years ago, and a new push for the cold-blooded theory.)

Still, you'd think that they'd mention that this isn't any huge surprise, as exiciting as this discovery is.

-Waldo

New evidence, old theory

[Joe Rumsey]

The idea that dinosaurs were warm blooded has been around for many years (I remember a book about it being on my dad's bookshelf in the 70's). It's widely (but not universally) thought to be correct by now. Finding something of the structure of one dinosaur's heart is just one more bit of evidence supporting the theory.

Re:New evidence, old theory

[HomeySmurf]

I believe you are refering to The Dinosaur Heresies by Robert T. Bakker. He was one of the first people to put forth the idea that dinosaurs were warm blooded, I actually believe he was the first. He was/is something of a maverik and published his results in newspaper articles and "popular" books such as this one instead of peer reviewed journals, and his thus his ideas took a while to catch on in the mainstream paleontology world. However, it is now a commonly accepted idea the field. (I think the male paleontologist character in Jurassic Park was loosely based on Bakker, but Bakker looks like a hacker).

It is now believed that birds are the direct descendent of the dinosaurs, eg the Archaopteryx which was the first bird-like creature to have feathers. However, it had teeth, a reptile like tail, and feathers on each wing. It is only known to be essentially a bird because of the preserved feathers. Indeed, feathers are really modified scales, wrapped around on themselves. They are hollow, and have fluffy parts to provide insulation, something especially helpful at higher altitudes. Without the feathers, it would have been mistaken for a small dinosaur.

This sort of points in the direction of feathers being a development after warm bloodedness. Cold blooded creatures would be at a disadvantage when they were trying to warm themselves in the sun if they were all insulated. This points to birds being, essentially, just another type of dinosaur with just a warmer covering.

There are numerous other indicators including the appearance of what appear to be channels for blood vessels in the skulls of dinosaurs. Warm blooded creatures need to control the blood flow to the head and to both keep it warm at times and also to cool it; reptiles don't need this feature. The long strides of the predator dinosaurs point toward fast metabolisms, unlike cold blooded reptiles today, etc.

This new evidence though points clearly toward the advanced circulatory system of dinosaurs. A reptile heart only has three chambers (indeed the medical condition of a septumless heart is refered to as a having a reptile heart, I believe). A four chambered heart is required for efficient circulation, and is a feature of birds and mammals. It really shows compelling evidence for dinosaurs being able to maintain homeostasis in body temperature.

(Not bad for a physicist, eh?

what the hell?

[jetpack]

I submitted this story in the goddam Creataceous period! And slashdot is just posting it now? I'm *sooooo* pissed off.

Re:Musings on warm-blooded vs. cold-blooded

[zCyl]

Evolution doesn't work quite like that. An entire category of animals isn't going to evolve a feature in unison. Evolution can be thought of as series of profitable mistakes, and while it is perfectly likely that some species evolved to be warmblooded, and then different dinosaurs evolved from that species, it is rather unlikely that all (or even that most) of the dinosaur types evolved warmblooded traits in parallel.

What would happen instead is one species eventually becomes warmblooded, and because of being warmblooded dominates the other species, eating their food supply. This then causes the warmblooded species to procreate more than the other species in the area, severely limiting the opportunities for the other species to make similar evolutionary advances.

Oh my god

[grappler]

Did I just read that post I'm replying to?

Dude,

oh man, I'm at a loss for words. Just...

Dude,

chill OUT. I doubt anyone on /. has any misconceptions about THAT...

geez

I wish you could see my fits of laughter I'm in right now.

--
grappler

Read "The Dinosaur Heresies"

[ericfitz]

Dr. Robert Bakker proposed this theory years ago. Here is his book.

broken hearted

[toh]

It seems likely that the AP headline write just missed the point (headlines frequently have little to do with the real discovery in a science piece). I seem to recall that it's been generally recognised for years (decades, actually) that dinos were probably warm-blooded (like birds), but finding a four-chambered heart with one large aorta sounds fairly new to me. A three chambered heart (like modern reptiles have) makes it difficult to exert large amounts of energy in a short time - a sprint, for instance - because returning venous blood gets mixed with the fresh oxygenated arterial blood from the lungs. A heart like the one they've found (more resembling that in birds or mammals) would be better for jumping around predator style, as my cat is having fun doing at the moment. Since dinos are supposed to be more the ancestors of birds than modern reptiles, this would seem to make sense.

Of course I could be off; it's been a while since evolutionary biology. Anyone remember the author and title of a Scifi mystery story where a creature's three-chambered heart was the deciding whodunit factor?

Musings on warm-blooded vs. cold-blooded

[Devolver42]

I find the entire debate to be amusing.First of all, much of the evidence for warm-blooded dinosaurs dates from the late Creataceous (meaning just before the Big Dino Die-Off); likewise, most of the cold-blooded evidence dates from the Triassic and early Jurassic periods (the early Age of the Dinos). Is it possible in the 150 million year gap that dinosaurs evolved to become warm blooded, because warm-bloodedness has distinct evolutionary advantages (speed, high metabolism in a food rich environment)?Just something I've mused over a lot.

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[account_deleted]

Comment removed based on user account deletion

Dinosaurs, birds and warm blood

[jw3]

Two comments. First, as other have already pointed out, thie idea that dinosaurs are warm blooded is quite old, now widely accepted and supported by lot of evidence. Second, biologically speaking, there ain't no such thing as "dinosaurs":this is a popular term designating two or three groups of distinct animals. A more apriporate term is "archeosauria", which also includes... birds. Actually, there are much less differences between birds and dinosaurs than between bdinosaurs and modern reptiles. Once you start to think about dinosaurs as bird-like animals, or, even much better, about birds a sdinosaurs which haven't died out, the idea that they were warm blooded is quite sound

Once again, I advice the pleno titulo Slashdot editors to ask some biologist before posting any media sensation they find. Look, for me, as a biologist, reading such "sensations" is more or less like for a Linux user reading a media coverage about a new Mindcraft test on Linux and Windows NT, clearly showing that Windows is superior.

I'm always sorry to see Slashdot to fall for any publicity made by Venter et. al. or any other scientist claimingthat he has discovered America.

Regards,

January

Then why did they dissappear?

[ContinuousPark]

I'm no paleonthologist but I remember reading somewhere that if an asteroid caused their extinction, it was because the cloud of dust has so thick that the sun couldn't pass through and so the dinosaurs, cold-blooded as they were, died, and the tiny warm-blooded mammals managed to survive.

So is this theory to be discarded? Was it even likely true sometime?

Re:This is new?

[Witchblade]

Um, yes. the news here is not that dinosaurs were warmblodded (the accepted view of paleontologists for at least a decade now) but the detail of the specimen itself.

As an aside rant this is what I hate about the "science" submissions on Slashdot. The Community knows far more about obscure networking cable adapters than junior high level scientific knowledge. As an astronomer I long ago got tired of even trying to contribute to the almost weekly astronomy story posted here. Think of all the stories you tell each other about AOLer's and newbie support calls. To a scientist y'all sound that bad sometimes. I'm sorry, but it's true. On the other hand most science discussions tend to quickly shift focus to the research hardware, or whether the analysts use PERL or Python, so the quality of the post go up, but it's no longer about scientific discoveries. Oh well. Guess this is just a single-interest audience. :)