Actually, Apatosaurs protected themselves from predation by referring to themselves as Brontosaurs, and making their escape while the carnivores bogged down in pedantic debates over nomenclature.
You do not want to see the carnage when a Roo hits a Jag. The Jag gets a huge dent in the front end (probably a smashed windscreen too) and the Roo will typically just jump over the nearest fence and bound away happily.
Hmm. What? Oh, sorry.
Don’t be silly. Obviously, the kangaroo leans back, balances on its tail, and kicks the jaguar in the head.
I think you’re underestimating the actual impact, double meaning intended, of the size difference. The apatosaurus weighs seven times as much as the allosaurus. If you’re a good-sized adult male human, you weigh around 200 pounds; imagine getting walloped by a 1400-pound opponent. All it has to do to damage you is run into you, basically; no agility required, just one good hit.
Now, imagine you’re a seven-ton bipedal carnivore. You get hit by, basically, what is comparatively a garbage truck, and fall on your side. One of your legs is injured, and you can’t really stand back up. You’re dead, whether it’s due to slow starvation or being ripped to shreds by the dinosaur equivalent of jackals.
Much easier and fantastically less risky to lurk around the fringes of the herd and hope for an unattended youngster, or to head down to the mud bog and look for a trapped and defenseless target, or better yet follow your nose for a carcass that hasn’t decomposed to the point of being inedible. Sure, there’s maybe a two in three chance you could take out an adult apatosaurus one-on-one, but a one in three chance of death in the attempt is a stupid gamble.
Oh, I forgot something:
I read somewhere that Spinosaurus had hollow teeth, which is one of the main components in speculation about its diet. True?
A lot of people seem to get the impression that all dinosaurs are interchangeable - they aren’t. Each species lived in a distinct time period, in a particular location.
For the most part, Allosaurus coexisted with critters like Stegosaurus, Camarasaurus (a sauropod which was much closer in size to Allosaurus, and thus a more likely prey species), and, of course, Apatosaurus, as well as competing predators like Ceratosaurus and Torvosaurus, and smaller ones like Ornitholestes.
As mentioned by Grendel’s Father, Tyrannosaurus didn’t even co-exist with Titanosaurus - in fact, sauropods in North America were pretty much non-existant by the time T. rex showed up (though some forms, like Alamosaurus, do show up again right at the end of the Cretaceous). Their primary prey (if they were predatory) would likely have been critters like hadrosaurs (“duck-billed” dinosaurs) or ceratopsians (like Triceratops).
One must realize that the defenses (or offenses) evolved by any species are going to be determined by what other species it had to deal with. Thus, one would not expect Apatosaurus to have evolved its large size as a defense against the likes of Tyrannosaurus. However, large size was more than sufficient to defend against the smaller Allosaurus. Later sauropods, such as Alamosaurus tended to have defenses other than mere size, since the large predators were getting larger, as well. So, we start to see more armored sauropods through the Cretaceous.
For their part, allosaurs had a fair number of choices in terms of what they hunted. There was no real reason for them to risk getting squooshed by a big ol’ Apatosaurus when there’s a tasty stegosaur nearby. Stay away from his tail and it’s probably an easy meal. There was no real pressure for allosaurs to evolve similarly-gigantic proportions because there was sufficient variety for them to get away with being simply “large enough”.
I haven’t heard about the “teeth being hollow” bit. Although, they are somewhat conical in appearance, rather than the typical “knife-like” shape of most theropod teeth, and have no serrations (or are very finely serrated) - rather like crocodile teeth, in many ways. The skull was also rather lightly constructed, with a narrow upper and lower mandible. And, fish scales were found associated with at least one Baryonyx specimen (which, except for the lack of big dorsal spines, is very similar to Spinosaurus), lending further credence to the fish-diet theory. It is possible that it also did some miscellaneous scavenging, as well.
I think a point made by Grendel’s Father needs to be reinforced:
There is a fundamental assymmetry in predator-prey relationaships–predators must incapacitate their prey (which often means kill), while the prey merely needs to injure the predator in order to make an escape. The prey animal has nothing to lose by fighting to the death, since that will be its fate anyway. But the predator cannot risk any substantial injury, unless it’s near starvation. There will always be another opportunity for a potentially easier meal.
What this means for this question, is that size offers a huge advantage. The sauropod only needs to get in one good hit to put a serious bruise (if not broken bones) on the carnosaur. The carnosaur won’t even risk attacking the sauropod if there’s any chance of injury, unless it’s literallly starving. The carnosaur needs multiple bites to take down the sauropod, unless it gets a lucky hold near the head. This is not a simple task.
(BTW, male (and not female) lions do manage to take down buffalo bulls by going for the neck and hanging on until it breaks or the bull suffocates. So it is possible for predators to take down vastly larger prey.)
As an aside, I’ve read that some scientists believe that the serrations in carnosaur teeth may have harbored septic bacteria, similar to komodo dragons’ teeth. The dragons will bite a prey animal and follow it (for days if necessary) until the toxins kill the prey. How would a sauropod defend against this?
I just happened to have picked up a paper today that touches on this topic, though there really isn’t any answer given beyond what we’ve already established here.
(Bakker, R.T. (1971). “Ecology of the Brontosaurs.” Nature 229: 172-174.)
What defence did hadrosaurids have against Tyrannosaurus?
An interesting article that touches on this.
Sauroposeidon, they had the same defense as a gazelle. Speed.
All of your assumptions about sauropods ability to defend themselves against carnosaur attacks imply that sauropods and carnosaurs would be operating on an even plane as far as speed and agility goes. Everything I’ve seen or read about sauropods and carnosaurs indicates that carnosaurs were incredibly agile and fast, and that sauropods were slow and clumsy.
So we’re not dealing with the equivalents of a 135-pound handball-playing accountaint going up against a 350-pound NFL defensive lineman. We’re dealing with the equivalent of a 135-pound professional boxer going up against a 350-pound couch potato. My prediction, the boxer’s speed and agility allows him to win without getting a scratch on him. In much the same way that an allosaur could leap on an apatosaur, do some quick damage, and leap back before the apatosaur could do more than bellow in pain.
As for my figures being a little off, I gathered them from various sources on the web. I saw several figures for each species named, and I generally went with the top figure for each that was within the range of the others. Could have been inaccurate there.
As for tyrannosaurs not coexisting with apatosaurs, no big deal. My main point was the defenselessness of sauropods like apatosaurs, I’m happy to go with the appropropriate species in whatever time period.
The rise of armored scales and clubs on the tail as top carnivores got larger in the Cretaceous does seem to argue that size alone may be sufficient up to a point, after the predator reaches a certain size in relation to you, you need armor or defensive weaponry.
It seems to be that the size of sauropods, combined with their ungainly body designs, makes them more vulnerable, not less, because slower and less agile. I understand that Bakker and others calculated the walking speeds of various species based on their anatomy, and I remember being surprised at how fast the carnosaurs were, even some of the big ones. I think the sauropods were fast, too, but not fast at all compared to carnosaurs. Further evidence of a huge gap between them in terms of speed.
May I point out that you are working from inadequate information and a self-described guess? Moreover, you vastly underestimate the agility of Sauropods. TV is not a good indicator. The real story seem to be that all dinosaurs could move prety fast and powerful when they need to.
regardless, you are basically working from the premise that Sauropds are doomed when the evidence says they must have been successful. Ergo, until you can present a better theory, scientists will ignore you.
No, too close in weight ranges. Try a 8 year old boy against a 400lb couch potato. No contest. Couch potato gets annoyed that boy is in the way of the view of the TV set and in one swing of his flabby arms boy goes flying. Except the boy better not get a cut and get infected because back in those days they didn’t have germ theory.
Watch a program about wolves hunting. A pack of wolves against even a moderate sized herd of relatively small animals has to be very careful and use planning to weed out the old and the sick. Wolves are much faster, agile and have seemingly much more dangerous armament, yet they have to be careful or they will die. Size is a huge deterrment.
I think you have a poor concept of combat and hunting. There is a world of difference between the analogy of animals and human.
One hit is all it takes. Oh, and there is a reason combat sports has weight classes. Yeah, the larger guy has the advantage. Take a 100lb boxer and put him up against a much less skilled 700lb giant and it is no contest(in favor of the giant). Look at Andre the Giant. And he was only about twice the weight.
Better yet- Take a 150lb expert swordfighter and see if he is confident enough to attack an unskilled 800lb Gorrilla with sword alone. Give him armor if he wants it. Full plate mail. I bet nobody, however skilled would be willing to do it. Size (and inversely strength, because there will be a strength difference) does matter.
First of, that’s only a 2x difference, when the actual numbers are much larger.
Put it this way: most people are only about 10 times as big as a large housecat, which is far more agile and has teeth and claws. But how many people do you think your housecat could actually take down? Now how many people in a pack of 10 humans do you think a housecat could take?
So help me out here.
I seem to recall seeing a show or lecture or something by Horner that indicated that the larger carnivores weren’t even true predators but mainly subsisted by either stealing another smaller predators kill or scavenging.
Something about the body structure and hip design lead him to believe that speed wasn’t in their arsenal but long distance smell and endless stamina for walking were.
Hazy…hazy…
Have you been reading the posts at all? Seriously. Nowhere has anyone assumed an equal plane in terms of physical capabilities. Everything has been about risk. The risk to the allosaurus in attacking a full grown apatosaurus would not be worth it when there were easier ways to get a meal around - like sick apatosaurs, young apatosaurs or other species entirely.
Sort of. Horner’s theory mostly applies to Tyrannosaurus, but this theory is hotly disputed. I think the comromise has been that adult Tyrannosaurs (and Allosaurs, etc) would hunt when young, but once they were big enough to fight off other predators they would take to scavenging the kills that smaller animals made since there was much less risk involved this way.
More than that; many scientists say there is no discernable distinction between scavenger and hunter; its a continuum. We simply have no idea what proportion of scavenging/hunting the T-Rex did.
Either way, I imagine the T-Rex had enough firepower and speed to take down some prey at maturity.
The Geological Museum at the University of Wyoming has the most complete Allosaurus skeleton found yet. It’s a rather interesting specimen because you can see all the wounds and battering it took during its life. In fact they suppose it was a broken foot that got infected that eventually killed it. National Geographic has recently done an article on dinosaurs and featured “Big Al” and was comparing him to Denver Bronco’s Mark Schlereth with all the injuries they sustained. It was by no means an easy life being a predator during the Jurassic era and it’s pretty representative that the prey species could more than ably avoid predation. Neither of the linked articles goes into too much depth, so I would suggest just actually finding the issue to get a better idea. Or if the urge strikes ya’, just tromp over to Laramie and see it for yourself. It’s not that cold right now.
Well, yeah, but what about a rabbit instead? He’s got huge, sharp-- eh-- he can leap about-- look at the bones!