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Re: Huge Freakin' Snake!

Quoting Augusto Haro <augustoharo@gmail.com>:

> Dann Pigdon said:
> > As David Marjanovic pointed out; modern snakes don't have large theropods
> or marine reptiles to
> > contend with. The difference between an anaconda and a jaguar is only minor
> by comparison.
> Difference in what sense? size, I suppose? Are you supposing that a
> snake the size of a theropod would be outcompeted while considering a
> snake the size of a jaguar lives along with the jaguar without being
> outcompeted? In such a case, why would they be outcompeted by a
> similarly sized theropod and not by a similar sized Carnivora?
> Or are you talking about some kind of unlikeliness of the development
> of the snake to reach the size of a big theropod when compared to
> reaching the size of the jaguar?

The latter. There are physiological constraints that set the upper limit of 
snake size. Titanoboa may 
well represent that limit. It's estimated weight is just over a tonne, which is 
considerably less than 
the largest theropods.

At the scale of an anaconda, a snake is probably about as fast as a jaguar (at 
least in initial 
bursts). Certainly an anaconda is physically stronger. I suspect a snake the 
size of Titanoboa was 
a slow-coach ambush predator - even more so on land than in the water (if it 
spent much time on 
land at all). The relative difference, both in size and escape speed, is far 
smaller between an 
anaconda and a jaguar than it would have been between a Tinanoboa-sized snake 
and a large 

> > Competition is certainly about more than shared prey items.
> Agreed.
> > One species can out-compete another
> > simply by keeping it out of prime habitat.
> That seems to be difficult to prove. As far as I know, jaguars dwell
> in the same microhabitats anacondas can do (trees, river, soil of the
> forest) yet they do not keep them out of prime habitat. 

Anancondas tend to hunt mainly in and around water. Jaguars tend to prefer 
terra firma. A jaguar 
near the water's edge is usually a nervous jaguar, while a fully-grown anaconda 
on dry land (in 
janguar territory) is probably equally nervous. The two species are fairly 
evenly matched - jaguars 
might be a bit quicker, more agile, and have better endurance, however 
anacondas are more 
powerful (and no slow-coaches themselves in short bursts).

> And how do you keep another thing out of their prime habitat? 

Killing it on sight is a good strategy. Where you find a lot of lions, you tend 
not to find a lot of 
cheetahs. There is little overlap between their prefered prey, however that 
doesn't stop lions from 
attempting to kill cheetahs on sight. If it wasn't for lions, cheetahs would 
almost certainly be more 
numerous than they are.

> We discussed the first case, the second seems weird for carnivorous
> vertebrates, and I have no reason why to think theropods would be any
> more violently damaging to a snake their same size than the snake
> against the theropod. 

Even if a snake had the same mass as a large theropod, it's greatly reduced 
speed and agility 
would have made it susceptable to a quick bite behind the head (ending the 
contest quickly). 
Walking around on stilts with your vital parts beyond easy striking range of a 
big slow snake might 
have emboldened a theropod in such an encounter (like a giant secretary bird).

> If you are thinking of theropods larger than
> snakes, then large felids commonly kill small felids in nature when
> they can, yet felids of different sizes still live one at the side of
> the other. 

Small felids are quicker and more agile that their larger cousins, they can 
easily hide if need be, 
and they have very keen senses giving them advanced warning of danger. A 
one-tonne snake 
would have been anything but quick, would have had trouble hiding, and it's 
sensory apparatus 
probably didn't have the range of a sharp-eyed, sharp-eared felid. Large 
ectotherm verses larger 
endotherm tends to be a more mismatched contest than that between medium-sized 
and small endotherm.


Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com