Gwangi Valley - Lost Blog of the Gwangi

Mistaken Premises are a lot like broken promises. They let you down in a profound way.

Today’s scrutiny falls on a fellow by the handle of Dinotheorist (http://www.dinotheorist.com). He’s a proponent of two ideas that bother me… in a profound way. The first is his assertion that dinosaurs were too heavy to walk and run in the Earth’s 1G gravity. The second is his notion (which follows on to the first) that the Earth mush have, therefore, had a lower gravity back in the Mesozoic.

At least he’s not a Neal Adams expanding Earth proponent. He thinks it’s to do with cooling and contraction. And he accepts evolution to be true. So he’s not all bad. In fact, he seems like a nice enough chap and I’ve seen him seek additional input from outsiders on a forum he frequents (but… Yahoo Answers isn’t the only place to look, old bean), even when it might be detrimental to his hypothesis. Nonetheless, I feel compelled to rain on his parade in one deluge here. (I did post on the forum seeking a response before posting here, but I haven’t heard anything. So off I go, eh.)

Below I’m going to take some quotes from his site and address some major areas of flawed data or thinking. There are several mistaken premises that snowball into an avalanche of fail. Also, there are several logical fallacies in each bit (collect them all for fun and prizes). We’ll start on the subtleties of extinction and then move on to bigger coelacanth… I mean fish.

Dinotheorist: “For each species that flourished, there are two possibilities as to why: 1) They were in a position to usurp the ecological niches of the organisms that failed, or 2) They already happenened to have physical equipment that was especially suited to the new environment. The most successful organisms may have had it going for themselves both ways.”

This is not a mistaken premise so much a a short-sighted one. Other organisms may have:
3) not filled a vacated niche but, instead, had the pressure from a predator taken away, allowing them to flourish. Animal A cannot survive, so its prey, Animal B, gets a break as a result.
4) been an organism for whom the flourishing of another organism (say, the one in #3, for example) is a boon to their own survival (parasites and scavengers, in particular, often tend to benefit in this way).
5) while not ideally suited to the changed world, but were just robust enough to last long enough to adapt.
This is mere nitpicking. Let’s get on to the more serious stuff.

Dinotheorist: “If the meteor was the only thing that killed the dinos, then birds and crocodiles should have been re-evolving back into dinos in a two-front evolutionary war against the mammals.”

This is a false dichotomy with a little straw man thrown in. It posits that one thing surely must follow if another does not. This is patently not the case. Crocodiles are on their own evolutionary path, not struggling to grow up to be a dinosaur. Also, he’s putting forth a goal-driven evolutionary modeal, as though being dinosaur-like is something crocs and birds innately aspire to. Crocodiles, for instance, are doing just fine as they are. They’ve done quite well for themselves, actually. There’s no selective pressure pushing them to war with mammals by growing into monsters. The entire statement just doesn’t go anywhere, I’m afraid.

I would offer a re-wording, if I may. “If a meteor was the only thing that killed the dinos, then crocs and birds couldn’t give a damn and would have gone about their business of being crocs and birds.”

Dinotheorist: “Why can’t crocs evolve longer legs and keep them? “

Why should they? It would impede on their ability to ‘be a crocodile’. Again, there is nothing pushing crocodiles to become a distant relative. There is no pendulum-like mechanism that’s centers at ‘dinosaur’. By that same logic, then, how is it that, now that you don’t have to hunt so hard for food and carry it long distances, you aren’t slumping back over and knuckle-walking?

Dinotheorist: “I will have to read more on where the vegetarian crocodile fossils have turned up, but I know they’re not alive today.”

Actually, there’s at least one living in China today. He favours rice. (I guess this is me nitpicking again. Sorry.)

Dinotheorist: “Bakker was right that dinosaurs moved very rigorously and reached high into treetops to feed. “Orthodox” paleontologists are right that dinosaurs were just too darn heavy. In modern gravity, they actually would be. The blood pressure in a sauropod’s head would drop too quickly when it is treetop feeding.”

Hold on there, before we start handing out the medals and saying everyone’s a winner… Which treetops are we on about?

If a Brachiosaurus stands 25 feet at the shoulder and the surrounding foliage is composed of ferns, cycads and equisetum, not the tallest of foliage, well… You see where I’m going with this, right?

And what ‘orthodox’ paleontologists are saying that our dinos could not have lived their life in normal Earth 1G gravity? For a proposal hinged on this very notion, there’s precious little evidence to support this idea. Actually… is there any? When biomechanics scientists talk about how fast a particular dinosaur might have run, they are basing their science on a 1G Earth. I’m aware of no one yet who’s put forth any ‘moon-based average speed’ for any dinosaurs, for instance. And I’m aware of no decent science that says dinosaurs needed lower gravity to live in.

Even John Hutchinson, who some (including our favourite loon Neal Adams) erroneously cite as having pronounced T. rex unfit to run at all (which is completely wrong), concedes that T. rex could have run at anywhere from 10 - 20 MPH (source - Nature). Just to clear the air, what Hutchinson said was that T. rex couldn’t run at the wishful-thinking speed of 45 MPH that some had suggested. (I have audio of Neal trying to cite Hutchinson, as an “I read somewhere once…”, and getting it totally wrong. A spectacular train wreck, he is.) A University of Manchester study agrees that around 18MPH is a good guess (source - University of Manchester). And a track of Megalosaurus prints found in Oxfordshire seem to indicate about an 18MPH run for an approx. 23 foot beast — which, to those who don’t know, is a close relative to T. rex (source - Nature).

I would turn the incredulous argument tables back on Dinotheorist: “Why didn’t this dinosaur run faster, if there was lower gravity? (By the way, its stride was very different for walking versus running. It walked like a chicken, ran more like an ostrich… or a mammal.)

Dinotheorist: “The bipedal hadrosaurs and therapods would have to “take it easy” or suffer joint problems in their legs. The four-legged, heavy ceratopsians would generate too much body heat too quickly as they galloped around.”

Umm… OK. Unless he’s arguing the old ‘all dinosaurs had arthritis’ saw (which isn’t true), then yes. Some dinosaurs would have had joint problems. Just like we humans do. And dogs do. In fact, many many animals, today and through history, have joint problems. (This is as good a place as any to mention that the two dogs in your website’s hypothetical have lung and heart issues and would, therefore, both be unsuitable for your trip.) But, nonetheless, dinosaurs walked and ran. We know this to be true. Even the ones with creaky joints. As for the ceratopsian assertion… I’m duty bound to point out that your lower-gravity ceratopsian, having the same mass, presumably now moving more freely, respirating more heavily in the thinner atmosphere… would likely generate just as much core heat as a 1G ceratopsian.

Dinotheorist: “John Boslough, the author of an excellent National Geographic article on gravity suggested that higher-gravity humanoids “might look like pancakes with short legs.” (May 1989, pg. 562). And a filmstrip presentation my fourth grade teacher gave to my class suggested a humanoid silhouette shaped like Arnold Schwarzenegger as the inhabitant of a planet with Jupiter’s gravity.”

Well! That proves it! OK… Smart-assing aside, this is all immaterial. Red herring. Straw Man. You name it. The fourth grade filmstrip, especially so. Neither we nor our dinosaur pals had to live in higher gravity. And, to cut to the chase, it is precisely that fact that has made life here amenable to both us and to enormous animals. 1G is really really good. 1G is marvelous! It’s part of why we’re here… and why Jupiter is not hospitable. If we had lower gravity, our atmosphere would be thinner, we’d have less radiation cover, it would be harder to get enough oxygen in our lungs and push it through to our muscles, pterosaurs would have had a harder time getting lift in the less dense air than in 1G, our hydrogen and helium would have leaked into space much faster (possibly too fast?)… you can see how this is all adding up to “not a good idea”, right? Our gravity is part of what makes our planet so damned awesome. Changing it is really really not a good idea.

Dinotheorist: “Picture the lunar astronauts bounding around on the moon…”

No. No, thanks. Why? Because that astronaut also has to live in an artificial atmosphere or he’ll die. This is how bad ideas propagate into the mainstream. There’s no argument or analogy there. The game is rigged. Imagine a Martian, then? No, the atmosphere on Mars is thin and most of it has escaped into space. This goes back to the previous bit: 1G gravity is good for you. And don’t disrespect the giraffe, man. Their necks are actually very good at pumping blood up to their brains. They don’t “barely manage”. It’s not ideal from our point of view, but nature has worked it out and it’s pretty damned elegant. A lesson, I might point out, we should take with us when discussing amazing creatures like dinosaurs.

What else… I feel I should tie up some loose ends before I stop. I haven’t addressed Dinotheorist’s entire post, but much of it hinges on things which, I feel, have already been unraveled above.

But there is still:
* - Haldane’s mouse down a mine shaft requires air resistance for the mouse to survive. It’s not a 1:1 argument.

* - Robert Bakker, who you cite repeatedly, had no issues with dinos walking and running in 1G.

* - Insects. Oxygen. On a lower gravity Earth, our prehistoric air would have been less dense and would not have been 30% richer in oxygen than it is today. And we know that it was. How? We can measure it, and, to top it all off, we now know that the large insects of the time could not have lived (and ‘breathed’) without this richer oxygen content.

* - One needs to be careful not to be myopic with these sorts of hypotheticals. Too often people will move, remove or change one variable and make an assumption based on that. But when you don’t take the resulting factors into account as a whole (ex. - lower gravity equals less dense atmosphere)… well, the phrase “jumping to a conclusion” is a good phrase.

If I could ask Dinotheorist to do only one thing, it would be to stop perpetuating the mistaken notion that dinosaurs were too big/heavy. There’s nothing to this idea and science left it behind long long ago. He should, too. Because… you know… people read something on the Internet and they assume it’s true.

Hey. Wait. I’m on the Internet…
Ella Rache