Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Dinosaurs May Have Been Neither Warm-blooded Nor Cold-Blooded

Soulskill posted about 2 months ago | from the bbq-sauce-for-blood-like-americans dept.

Science 54

An anonymous reader writes An article published in Science (abstract) points to the possibility that dinosaurs were mesotherms more akin to modern Tuna. Their internal temperature would have been warmer than their surrounding environment, conferring on them the ability to move more quickly than any ectotherm ("cold blooded" animal), but wouldn't have been constant or as warm as any endoderm ("warm blooded" animal). Their energy use and thus their necessary food intake would have been greater than an ectotherm, but much less than an endotherm. In order to arrive at this possibility, bone growth rings in fossilized bone were used to establish growth rates and then compared to modern ectotherms and endotherms.

cancel ×

54 comments

Sorry! There are no comments related to the filter you selected.

Interesting article (-1, Troll)

Gothmolly (148874) | about 2 months ago | (#47232789)

This is a very relevant study.

ohmygodwhothehellcares.jpg

Interesting article (-1)

Anonymous Coward | about 2 months ago | (#47233153)

Science is dumb. Let's go shopping!

Re: Interesting article (1)

Jeremiah Cornelius (137) | about 2 months ago | (#47238921)

I think that Dinosaurs were magical trees, fueled by the energy of the stars and filled with aetheric pitch or sap, that responded to the vibratory symphonies described by the planetary epicycles.

It is said that the largest dinosaurs had two brains - one in the head and another near the tail, like a fireman driving a ladder truck. This is nonsense. Dinosaurs know nothing of firemen, even if one factors their trans-dimensional aspect into consideration. This is because the creatures never had two brains, or even one brain to speak of. The cranium of a dinosaur contains only timecube, all the way down.

The Goldilocks Institute (1)

Anonymous Coward | about 2 months ago | (#47232813)

Scientists have deemed it "just right".

Re:The Goldilocks Institute (1)

K. S. Kyosuke (729550) | about 2 months ago | (#47233391)

Blood temperature level: Aladino.

Re: The Goldilocks Institute (1)

Jeremiah Cornelius (137) | about 2 months ago | (#47238919)

Neither warm nor cold, bird nor reptile.

I think that Dinosaurs were magical trees, fueled by the energy of the stars and filled with aetheric pitch or sap, that responded to the vibratory symphonies described by the planetary epicycles.

It is said that the largest dinosaurs had two brains - one in the head and another near the tail, like a fireman driving a ladder truck. This is nonsense. Dinosaurs know nothing of firemen, even if one factors their trans-dimensional aspect into consideration. This is because the creatures never had two brains, or even one brain to speak of. The cranium of a dinosaur contains only timecube, all the way down.

Relation of birds to dinosaurs (5, Interesting)

jphamlore (1996436) | about 2 months ago | (#47232815)

So did the dinosaurs become birds or were they parallel evolved species after some earlier branching point?

Re:Relation of birds to dinosaurs (5, Funny)

wisnoskij (1206448) | about 2 months ago | (#47232873)

Obviously Dinosaurs became Tuna.

Re:Relation of birds to dinosaurs (0)

Anonymous Coward | about 2 months ago | (#47233015)

No, dumbass, Dinosaurs CAME FROM Tuna. Duh.

Re:Relation of birds to dinosaurs (0)

Anonymous Coward | about 2 months ago | (#47233045)

So dinosaurs were aroused by tuna pussy?

Re:Relation of birds to dinosaurs (2)

NatasRevol (731260) | about 2 months ago | (#47233033)

Impossible. There's nothing in between! They couldn't have just made that jump! I'm not a monkey's uncle!!

(sarcasm, for the humor impaired)

Re:Relation of birds to dinosaurs (1)

Anonymous Coward | about 2 months ago | (#47233463)

You can tune a piano but you can't tuna... dinosaur?!

Re:Relation of birds to dinosaurs (0)

Anonymous Coward | about 2 months ago | (#47233893)

Obviously Dinosaurs became Tuna.

The chicken of the sea.

Re:Relation of birds to dinosaurs (0)

Anonymous Coward | about 2 months ago | (#47235311)

> Funny

Evolution by natural selection
(Score:-1, Funny)

Re:Relation of birds to dinosaurs (3, Insightful)

Anonymous Coward | about 2 months ago | (#47232961)

"Dinosaurs" werent just a single species. There were quite a lot of them. Some of them developed feathers and went on to become birds, some stayed in the water and went on to become Nessies, but most of them just plain died and their descendants didnt evolve into anything.

Re:Relation of birds to dinosaurs (0)

Anonymous Coward | about 2 months ago | (#47233011)

No dinosaurs lived in the water.
Not even all prehistoric land "reptiles" where dinosaurs.
But yes, your basic point is correct. Not all dinosaurs evolved into birds. Birds evolved from a subset of dinosaurs.

Re:Relation of birds to dinosaurs (1)

Noah Haders (3621429) | about 2 months ago | (#47233309)

No dinosaurs lived in the water.

but what about the ictheosaur and all those other ones? and megaloposhark?

Re:Relation of birds to dinosaurs (4, Informative)

mrchaotica (681592) | about 2 months ago | (#47233759)

Ichthyosaurs, Plesiosaurs and Mosasaurs are Lepidosaurs (the group containing lizards and snakes), which is a different branch off Diapsids from Archosaurs (the group containing dinosaurs and birds and crocodiles). Megalodon is a shark, which is a kind of fish and therefore not even a Diapsid.

Re:Relation of birds to dinosaurs (1)

Noah Haders (3621429) | about 2 months ago | (#47234067)

i see. amateur hour as usual. wikipedia much?

Re:Relation of birds to dinosaurs (1)

KillAllNazis (1904010) | about 2 months ago | (#47234551)

You are technically correct; the best kind of correct.

Re:Relation of birds to dinosaurs (1)

mpe (36238) | about 2 months ago | (#47237749)

"Dinosaurs" werent just a single species.

They are not even a single class. In the 19th century they were divided into "reptile hip" and "bird hip". So even that long ago it was clear that at least two distinct types of animals were involved.

Some of them developed feathers and went on to become birds

Whilst theropods are related to modern birds (Aves) it's unclear how, and when, feathers evolved.

some stayed in the water and went on to become Nessies

Plesiosauria, and other aquatic animals are not technically "Dinosaurs" anyway. Possibly they evolved from land animals, in a similar way to Cetacea.
Pterosauria arn't "Dinosaurs" either.

Re:Relation of birds to dinosaurs (0)

Anonymous Coward | about 2 months ago | (#47232991)

They became FAB-YOU-LOUS!!!

Birds (1)

art6217 (757847) | about 2 months ago | (#47232833)

Sounds likely, if birds are their warm-blooded descendants.

New theory? (5, Interesting)

Anonymous Coward | about 2 months ago | (#47232861)

TFA makes this sound like a new theory, but the first time I read an article proposing this (with supporting evidence) was at least 20 years ago, and may well have been longer ago than that.

It's nice that they've come up with more evidence for it, but it would also be nice if every time someone tested an idea out they didn't feel compelled to pretend they were the first to have it.

Re:New theory? (4, Interesting)

Oligonicella (659917) | about 2 months ago | (#47233085)

Yep. Paleontology is a field rife with one-upmanship. Cold blooded, warm blooded, hot blooded and meso. All had their day multiple times. My personal belief is that the theropods were most likely hot-blooded like the birds and the sauropods were meso-blooded. Their respective activity levels make this likely to me.

Re:New theory? (1)

Anonymous Coward | about 2 months ago | (#47233581)

And that modern day theropods are warm blooded doesn't hurt your theory either.

Re:New theory? (1)

Anonymous Coward | about 2 months ago | (#47235711)

Sauropods are closely related to theropods and were so huge that they probably had a harder time losing heat than gaining it. They required a temperature stabilizing system so that puts them well into "hot-blooded", rather than tuna liquid-cooled overheating muscle, territory.
The last common ancestor of all dinosaurs was a theropod-like insectivorous animal, closely related to the ancestors of pterosaurs which are most likely hot-blooded again.
I could see some dinosaurs having a low-temperature endothermic metabolism like the modern Monotrema, or some rare cold-blooded throwback, but hot(as in stable controlled temperature) had to be the default.
At this point, I wouldn't even dare to put extinct cocodrilians into the cold-blooded basket. They had a four-chambered heart and mostly erect limbs and were likely very active.

Re:New theory? (5, Informative)

Anonymous Coward | about 2 months ago | (#47233119)

It's nice that they've come up with more evidence for it, but it would also be nice if every time someone tested an idea out they didn't feel compelled to pretend they were the first to have it.

I think this is a very unfair attack. The authors of this paper did not make the claim you've attributed to them. They start the actual article with this.

Over the past few decades, the original characterization of dinosaurs by early paleontologists as lumbering, slow-metabolizing ectotherms has been challenged.

There are 397 references given in this paper. I think they're clear about what previous science existed. Even the lay article doesn't pretend this is new research it talks about compiling existing research.

Re:New theory? (0)

Anonymous Coward | about 2 months ago | (#47235527)

the slashdot summary makes it sound like it, you should know by no that noone reads tfa

No it doesn't. (0)

Anonymous Coward | about 2 months ago | (#47237401)

I'm not sure how, in your world, "points to the theory" becomes "holy fucking shit, this is totally new shit". If I pointed to a Starbucks, would you take that as a claim that I "discovered" Starbucks?

Re:New theory? (0)

Anonymous Coward | about 2 months ago | (#47233295)

I first read a 'neither warm nor cold blooded' theory more than 30 years ago.

Re:New theory? (2)

Princeofcups (150855) | about 2 months ago | (#47233975)

After several false starts during which she repeatedly and noisily attempts to clear her throat, Ms. Elk spends most of the interview circuitously leading up to the "theory of dinosaurs by Anne Elk bracket Miss brackets", making assertions like "My theory, which belongs to me, is mine." It turns out that in the end Miss Elk's new theory on brontosauruses is rather shallow: "All brontosauruses are thin at one end, much, much thicker in the middle, and then thin again at the far end." Her true concern is that she receive full credit for devising this new theory: "That is the theory that I have, and which is mine, and what it is too."

false dichotomies are everywhere (1)

Anonymous Coward | about 2 months ago | (#47232897)

Now that the false dichotomy between cold-blooded and hot-blooded has been debunked, let's work on that pesky false dichotomy between animals and plants.

They were cooooool-blooded (-1, Troll)

NotDrWho (3543773) | about 2 months ago | (#47232905)

Just like Gary and Mike on WZXR, 103.5, THE BOMBER SQUAD!!

Re:They were cooooool-blooded (0)

Anonymous Coward | about 2 months ago | (#47232915)

You see, son, this kind of thing is what makes you a moron in everyone's eyes.

paleontology research funding (0, Flamebait)

Anonymous Coward | about 2 months ago | (#47232919)

As a side note, republicans have quietly cut funding over the years for dinosaur research to support their creationism agenda. We will see less and less of this type of great paleontology research largely due to the United States.

Re:paleontology research funding (1)

Anonymous Coward | about 2 months ago | (#47232945)

As a side note, republicans have quietly cut funding over the years for dinosaur research to support their creationism agenda. We will see less and less of this type of great paleontology research largely due to the United States.

Oh please, does every slashdot article always have to turn around to and become a USA bashing fest? This article is about *dinosaurs*. The obsession with slashdot in finding ways to bash the USA lately isn't normal or sane.

Re:paleontology research funding (0, Troll)

Anonymous Coward | about 2 months ago | (#47232977)

Yes. The USA is a shithole. It needs repeating in every article.

Re:paleontology research funding (1)

mattack2 (1165421) | about 2 months ago | (#47234255)

This article is about *dinosaurs*.

Yes, Republicans, which is what he said.

(BTW, I am registered R.)

Re:paleontology research funding (0)

Anonymous Coward | about 2 months ago | (#47232999)

All the dinosaur researching you need is in The Holy Bible and can be seen at the Creationism Museum!

"And Yea, when Adam and Eve were kicked out of the Garden, their pet Velociraptors and Bronciosaurs were no longer tame, and they were hunted to extinction due to being large and slow." Genesis 15-8

Re:paleontology research funding (0)

Anonymous Coward | about 2 months ago | (#47233025)

Lies! Jesus rode a dinosaur in his travels through the Middle East. Take your blasphemy elsewhere, devil-spawn!!

Re:paleontology research funding (0)

Anonymous Coward | about 2 months ago | (#47233069)

Lies! A dinosaur rode Jesus in the middle east, leaving him with a sore gaping arris.

Re:paleontology research funding (0)

Anonymous Coward | about 2 months ago | (#47233109)

The idiot troll even manages to make stupid comments on this topic. What a moron.

endo/ectotherm (1)

PPH (736903) | about 2 months ago | (#47232947)

Are these classifications entirely distinct? Or do we see animals existing along a range from one end to another?

Re:endo/ectotherm (1)

Charliemopps (1157495) | about 2 months ago | (#47232979)

Read the article:

Today, that middle ground is occupied by animals including tuna, lamnid sharks and leatherback turtles.

Re:endo/ectotherm (0)

Anonymous Coward | about 2 months ago | (#47237439)

While I typically don't want to give into the discontinuous mind, they are.

Endotherms maintain an internal temperature within a narrow range effectively regardless of the external temperature.
Ectotherms have their internal temperature almost entirely governed by their external temperature.

Mesotherms maintain a consistently higher temperature than ectotherms in cooler environments, but do not maintain a temperature in a narrow range. Think of it like ectotherm + a given number for the species, say +10.

So... (0)

Anonymous Coward | about 2 months ago | (#47232955)

...juuust right!

Ektatherm (-1, Flamebait)

Kerstyun (832278) | about 2 months ago | (#47233471)

In my day we called 'em cold-blooded. Also, fuck beta. And niggers.

I'm getting tired of these meaningless blood terms (-1, Flamebait)

holophrastic (221104) | about 2 months ago | (#47233523)

Look, it's very simple. If the animal alters the temperature of its own blood, to be different than the environmental temperature, by anything more significant than standard locomotion (we won't count walking to the toilet, but we will count routinely running on a treadmill), then the animal is warm blooded.

I don't care if it's controlled to a constant temperature, and I don't care if it's through metabolic activity, muscular activity, solar receptors, or nuclear fission reactors.

Case in points: I am warm blooded, even though my blood temp drops by as many as 2C in the cold. I am also warm blooded even when my blood is colder than the environment in the summer. Warm has never meant warmer. Warm has never meant constant. Warm has never meant controlled. Warm has only ever meant changed.

Everything else is simply the same set of lies, twisted and contorted to over-simplify an observation or to over-fit a given hypothesis.

No one has ever thought that dinosaur blood was always the same temperature as the environment. And that doesn't make them cold blooded. And it doesn't make them warm blooded. And it doesn't make them neither. And it doesn't make them both. It mades you argumentative for absolutely no reason.

You're wrong, these aren't meaningless. (0)

Anonymous Coward | about 2 months ago | (#47237511)

To paraphrase what I've said elsewhere in this thread. These are distinct, meaningful, well defined terms.

Endotherms maintain an internal temperature within a narrow range effectively regardless of the external temperature.
Ectotherms have their internal temperature almost entirely governed by their external temperature.
Mesotherms maintain a consistently higher temperature than ectotherms in cooler environments, but do not maintain a temperature in a narrow range.

You are an endotherm not because you're always 37 C, but because you're never 31 C or 43 C and alive.
A lizard is an ectotherm because if it's 20 C out, he'll be close to that.

A dinosaur could be classified a mesotherm if it were 20 C and he was 26 C, or if it was 15 C out and he was 21 C or if it was 24 C out and he was 30 C. The warmer temperature allows him to outrun his crocodile lunch.

The value to these classifications is that they allow you to understand important aspects of a new species almost instantly.

To go your way, to say any temperature modification regardless of source means "warm blooded" would to be classify everything thusly and render the whole deal meaningless.

This is why you ought to be ignored.

They just were. You MUST BELIEVE it. It's science! (-1)

Anonymous Coward | about 2 months ago | (#47235305)

Scientists are sometimes more stupid than religious people.
Remember this when you listen to one.

I know (0)

Anonymous Coward | about 2 months ago | (#47235827)

They're Kombat Blooded.

the lecture I didn't receive (1)

epine (68316) | about 2 months ago | (#47236755)

I first posed the question to my elementary school science teacher circa 1973 whether the dinosaurs weren't in some way usefully self-warming. I didn't have the vocabulary about homeostasis or mesotherms at that age.

***

So, young man, you're suggesting that the dinosaurs might have been mesotherms?

"Meso", everyone, means "in between" or "intermediate". So the idea here is that dinosaurs would be warmer than modern reptiles but not as warm as modern mammals—whales and cats and dogs and humans and horses—who maintain a fixed body temperature. By "fixed" temperature we mean within a narrow range, subject to regulation, or control. Among the regulatory abilities in humans are sweating when we get too hot, and shivering when we get too cold. (Does anyone know if whales shiver? Someone try to find that out for class tomorrow.) When our body temperature regulation fails we experience fever or chills. Chills are known to doctors as hypothermia, "hypo" meaning reduced and "thermia" meaning temperature; hypothermia means "reduced temperature". Fever and hypothermia are dangerous conditions that require prompt medical attention.

It's different when a lizard gets cold. For the lizard it's not an immediately dangerous condition; it just becomes sluggish until its environment warms up again. Now our lizard might be subject to predation—being eaten by a predator like an eagle or a snake—if it becomes sluggish at the wrong time or in the wrong place.

Mammals are the opposite in both ways: our temperature remains fairly constant regardless of our environment, and when our body temperature—not in our arms and legs and hands and feet, but inside our skull, our chest, or our belly—when this internal temperature changes, that's a big thing to worry about.

A mesotherm would be an intermediate creature, one who is able to generate enough body heat to remain active in a cold environment, which helps to avoid predation (remember that means being eaten), but isn't directly threatened by having a cold body temperature, if the food supply does not support maintaining a high activity level.

Something science has learned is that any organism that goes too long without food ceases to generate warmth internally. Now a large pile of dead plant matter—yard waste—can become much warmer than the surrounding environment, but this is due to smaller organisms with the plant matter which are busy eating the plant matter. It is also true that rotting meat will generate warmth from the small organisms inside the meat causing the meat to rot. Whatever the situation, if heat is being generated in a biological system, somewhere in that system there is some form of digestion taking place.

Now let's go back to the excellent question about dinosaurs could have been mesotherms. As young scientists, you are probably all wondering what is the evidence that dinosaurs were cold blooded or not. That's a very good question, everyone.

As a scientist, I wondered this myself. As a scientist we are trained to ask these questions whenever possible and seek as hard as we can to obtain the answers. Over my summer holidays—can you believe that?—I scoured all the science textbooks available to this school district, and I can't find a single sentence in any book explaining why dinosaurs are believed to be cold blooded, apart from their having a distant kinship with modern reptiles.

But then, think about this yourself. We know modern reptiles are much smaller than dinosaurs, who were waaaaay bigger than elephants. Large creatures often generate more heat than they want to have, which is why elephants have those giant, thin ears. All that extra skin helps them to transfer unwanted heat into their environment.

We'll be talking more about the relationship between heat and temperature in future classes. This is an important concept which is central to life as well as to modern machinery, which is why we eat regular meals and our cars visit gas stations. Heat and temperature are both connected to the concept of energy. That's a very important concept you'll be visiting year after year in your school education.

Unfortunately, it appears that all your textbooks—all the way until you leave school when you are much older—we written by the same idiot, who isn't a proper scientist at all. So we're all going to have to work hard to figure out our own answers to these important questions by thinking carefully in our own minds and challenging each other to support our opinions.

Does that sound like a good idea? Yeah, it does, doesn't it.

[Intercom buzzes.]

Well, my young students, I suspect that would be the principal's office summoning me to the guillotine for my immediate beheading.

I love you all, and I'll miss you so much. Good-bye everyone. It was worth it.

Spelling mistake (1)

jchevali (171711) | about 2 months ago | (#47241745)

Seems that "endoderm" is wrongly spelled.

Check for New Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>