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RE: Ceratopsian frills



[ After you read this message, you might want to take a look at Tom
  Holtz' classic post on Theropod hunting strategies.  Thanks to David
  Condon at the Cleveland Museum of Natural History, we don't have to
  repeat it here because you can see it at:

  http://www.cmnh.org/fun/dinosaur-archive/1995Aug/0746.html

  -- MR ]

Stephen Throop wrote:

>My explanation goes back to predators.  I don't think teeth were a good
>way for a carnosaur to attack an animal weighing several tons.  (In our
>world, it is apparently not feasible to prey upon the largest
>plant-eaters.)

Teeth work reasonably well as long as they are big.  Smilodons apparently 
succeeded in bringing down the giant ground sloths or young mastodons.
The most plausible reason we don't see predators around that go after the 
larger prey is us.  Humans don't like competition.

>With its short, powerful neck, a dog can move its head with blinding
>speed.  Wouldn't a carnosaur, with its much longer neck, have had
>trouble being quick enough to bite uncooperative prey in a vital spot? 
>How long could a carnosaur afford to fool around?  If modern crocs are
>any indication, the tails of dinosaur prey could be lethal.

Snakes and a variety of birds, ala ostriches and secretarybirds, display 
blinding speed as well without the need of the short neck.  Yes, I know 
people may argue the snake neck length, but their body usage in strikes is 
analogous to a long neck.  In addition, that extra neck length provides 
more force to the blow if needed.  Believe me, you don't want to be pecked 
at by an ostrich.  I have been told by zookeeper friends of mine that their 
scrawny little necks can amazingly strong and can inflict serious injury.  
Although a point in your favor is the return after the strike which I 
believe would be slower so the short neck does have the advantage in 
quicker second strikes.

>What bite will kill a large animal instantly?  In clinging to violently
>moving big game, a big cat uses its claws to augment the strength of its
>short neck.  Carnosaurs were long animals with long necks, and the
>ultimate carnosaur, T Rex, had useless arms.  How did such predators
>avoid broken necks or being thrown off?

Hard to say since the big theropods most likely used different attack 
styles than that seen today.  The large cats kill their prey predominantly 
by suffocating them to death rather than actually clawing and biting them. 
 They have the endurance and resilience to do that whereas it is unlikely 
that a T Rex could manage such a feat.  Canids on the other hand tend to 
wear out their target by repeated attacks and feints by several members so 
that they can pretty much kill the prey at their leisure with numerous 
wounds.  This sort of attack has often been postulated for the smaller 
theropods.  T Rex and his ilk either went after prey that it could easily 
subdue like the duckbill clan or young it could snatch from unwary parents, 
or it could have hunted in canid like packs to take down the bigger and 
more dangerous prey as hs been suggested before by others.  And I wouldn't 
exactly say that T Rex's arms were useless.  Didn't Horner estimate the 
strength of a single T Rex arm at around 400 lbs or am I misremembering?  I 
am not saying they weren't useless, but it is possible that they were used 
in ways that have not been examined yet.  The proper leverage can make that 
400 lbs go a long way.

>In addition, I understand that T Rex's huge teeth were too fragile to
>attack large living prey.

I have heard that too, although I don't remember where.  I have a hard time 
seeing how those teeth are anything approaching fragile.  They are at least 
as strong as crocodile teeth or shark teeth and they do just as well.  
Remember, the strength of the teeth needn't be scaled upwards to their body 
size or anything like that.  They simply have to withstand cutting through 
flesh and maybe bone and that they do just fine.  The size of the piece 
they cut through doesn't really matter.  Besides, they grew back fairly 
quickly so if they lost some regularly, so what?
  
>To avoid danger from a tail, I think a big carnosaur charged big game
>from the side and disabled it by breaking its neck.   It appears that
>the strength of a large carnosaur was concentrated around its rear
>limbs.  I think such animals delivered devastating blows by leaping
>feet-first, like a rooster or a martial-arts expert.  

Naturally its strenth was concentrated in its legs.  So is yours and any 
other bipeds.  I know my legs can can lift an order of magnitude than my 
arms can.  But which one am I likely to use in attacking someone?

>Jumping this way would also have reduced a predator's vulnerability in
>case the prey swung its tail in time.  Even if the carnosaur failed to
>break the prey's neck, knocking the prey down would be a big advantage.

Actually, jumping completely off the ground in some kind of a grandiose 
highflying kick increases your vulverabilty rather than the opposite.  
While in the air they would have little control so if the target had, say, 
horns, and turned them into the oncoming jump, the theropod would be 
screwed.  That is why you don't see a whole lot of kicks like that in 
martial arts tournaments.  They are only done at a time when they think 
they can surprise their target with them.  A watchful opponent makes this 
tactic very dangerous to the one trying it.
Having said that, I do think that it is likely the dromaeosaurs acted like 
that commonly.  But then, that is what practically everybody says.  

>It seems that most Sauropod necks were only 2 or 3 meters off the
>ground.  

If this was true and I have no reason to think it was not, at least some 
point of their length, it makes them prime targets for any sort of attack.

>Cretacious Ankylosaurs reverted to the low, wide-tracked sprawl of their
>remote ancestors, as well as evolving short necks, closed skulls, and
>large masses.  These sound like countermeasures to blows, not bites.

>Ceratops also had short necks and wide, low sprawls.  They evolved large
>masses.  

While it is certainly true that it would protect from blows better than a 
long open frame, why would it not also help against bites?  If you increase 
the girth of a limb it becomes much harder for a bite to have serious 
effect.  I can disable my arm by cutting far easier than my leg because the 
blood vessels and tendons and bone is less well protected than in a larger 
limb.  These animals also developed armor.  It seems to me that their 
defenses could go for both quite easily.

>Wouldn't the frill have braced the Ceratops's neck against a blow from
>the feet of a leaping predator?  Such a brace would have been
>particularly effective if it were loosely attached to the torso, like a
>shoulder blade.

True, but I doubt the frills were strong enough to fend off the body mass 
of a predator very effectively.  I tend to agree with those that say the 
frills, while possibly starting out as something defensive or for muscle 
attachments, became much more elaborate to the extent they did for sexual 
displays, as did the horns.

>How about the horns?  My goats have never used their horns against me,
>but I don't dare lunge at a goat with abandon because I could impale my
>eye or abdomen by accident.  This caution makes it much harder to catch
>a goat.

They haven't?  My zookeeper friends have certainly had this happen to them. 
 In fact one of them had an antelope stick his horn all the way through his 
leg one time.  So I would have to agree with you, sexual display or not, 
any predator is going to think twice about attacking an animal with horns.

>I think the primary advantage of the Ceratops's frill was to brace the
>neck against a blow by a leaping predator.  In addition, the horns would
>have made such attacks risky. The Ceratops's big tail and nasty bite
>would have discouraged more cautious attacks.

Regardless of the particulars, I would tend to agree with you that the 
Ceratopsians probably didn't make anybody's list of favorite prey items.

Joe Daniel