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Re: Lack of Running Giant Theropod Tracks
On Fri, Dec 3rd, 2010 at 1:06 PM, Augusto Haro <firstname.lastname@example.org> wrote:
> 2010/12/2 Sim Koning <email@example.com>:
> > Adult tyrannosaurs, although slower, would have been able to kill
> > ceratopsids and
> animals that the juveniles may have been too weak and blade-toothed to
> exploit. However,
> living by attacking something that is not only your own size, but also able
> to kill you as easily
> as you could kill it, may not have made for a very survivable lifestyle.
> This does not seem easy to infer. For example, the weaponry of a rat
> or squirrel (their incisors) make them probably very dangerous for a
> similarly sized predator, yet many weasels make a living mostly of
> eating these similarly sized rodents...
Indeed; many carnivores regularly take on potentially dangerous prey. Lions
will target Cape
buffalo, even though they could look for easier prey if safety was their
primary concern. Yet
experienced lions still target such dangerous prey, because the potential gain
from killing such a
large creature often outweighs the increased risk. I think the key word there
Recent studies in sub-adult Great White sharks suggest that their jaw bones
aren't strong enough
for them to tackle large mammalian prey properly until they reach about 3m in
This doesn't stop them from attempting such attacks; however they tend to abort
after just one
exploratory bite. The danger to the shark isn't from the prey harming them in
defense, but in the
shark's jaw muscles breaking its own jaw in the attempt to feed. I imagine a
might suffer a similar fate trying to subdue a well-armoured thyreophoran,
whereas a much older
individual may have had the necessary equipment to power through that armour.
dangerousness of the prey may have been a secondary concern.
Also keep in mind that people tend to think of the huge 12m tyrannosaurs as
'adults', and anything
smaller as 'sub-adults'. If tyrannosaurs continued to grow throughout their
lifetime, as modern
crocs do, then they may well have reached sexual maturity (ie. 'adulthood') at
much smaller sizes.
The 12m long behemoths may have just been unusually long-lived individuals,
representative of the normal adult state.
Spatial Data Analyst Australian Dinosaurs
Melbourne, Australia http://home.alphalink.com.au/~dannj