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Re: Tyrannosaurus Tail Torqueâ



--- On Sun, 11/21/10, Sim Koning <simkoning@msn.com> wrote:

> -----
>  
> Regarding Komodo dragon's and their bite. Watch the video
> and you'll notice that the dear's leg is *rotting* due to a
> bite. They walk up to ungulates and bite them on the leg,
> they get an infection and then they track them down and eat
> them while they are still alive. There are plenty of other
> videos showing them biting animals on the leg for the same
> reason. These animals eat rotten *putrid* meat on the
> shoreline... you WOULD NOT want to get bit by one. 
>  
> http://www.youtube.com/watch?v=KfTgkJHpdsM

++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Not to get too off on a tangent here, but this is the non-sped up version of 
the video you linked to, with the relevant section highlighted. 

http://www.youtube.com/watch?v=ViisuDKqKuI&t=6m53s


Documentaries are tough to judge for examples of animal behaviour as one must 
take into account how the footage was chopped up to "tell the story." In this 
case, it looks like the entire attack took place in one day. The actual attack 
takes place at 7m44s, assuming it is the same deer (if slowed down enough one 
can see the deer that was attacked had a healthy left rear leg). 

The point remains that there has never been a credible observation of Komodo 
dragons using bite and release as a means of killing their prey (the dragon in 
the video backs away at one point for what looks like "fear" of retaliation 
from the deer before it collapses). 

Walter Auffenberg (1981) took extensive notes on his observations of wild 
dragons hunting. His notes include observations on natural attacks, as well as 
staged attacks (where his team tethered a goat to a post and waited for a 
dragon to come by). In the case of the latter, he also took pictures and 
drawings of the killing process. At no point in these attacks did the dragon 
ever just walk off and wait for the animal to die. In fact it was quite the 
contrary, with Auffenberg describing the attacks as extremely violent affairs. 

Fry et al (
nd that it causes hypotension (as demonstrated at 8m28s in the video) which 
seems to aid dragons in taking down large prey, but in no means is this their 
primary mode of hunting. 

Honestly the only reptiles that have ever been shown to reliably use a "bite 
and release" strategy are vipers. 

_____________________________________________________________
>  
>  
> Also, more on topic. Do you guys think it's possible that
> giant theropods could have had an elastic strain energy
> storage tendon/s in their lower legs (like macropods) that
> may have given them more "free" energy while running? I was
> just reading about how such a system remains efficient even
> when weight is increased. I also suspect that the
> caudofemoralis was very elastic and may have stored energy
> as the tail "wagged" side to side. What do you guys think?

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Muscles can store strain energy, though it is often small compared to the 
storage capacity of tendons (Alexander & Clark 1977). I don't know if any 
elastic storage tests have been performed on the caudofemoralis, though it 
would appear to be plenty powerful enough to handle long walks, or bursts of 
acceleration all on its own.

More on this very subject in the very near future. :)

Jason

References

Auffenberg, Walter, 1981, The Behavioral Ecology of the Komodo Monitor, Florida 
University press, pgs: 406.

Alexander, R.MCN., Bennet-Clark, H.C. 1977. Storage of Elastic Strain Energy in 
Muscle and Other Tissues. Nature. Vol.265:114-117

Fry, B., Wroe, S., Teeuwissed, W., van Osch, M.J.P., Moreno, K., Ingle, J., 
McHenry, C., Ferrara, T., Clausen, P., Scheib, H., Winter, K.L., Greisman, L., 
Roelants, K., van der Weerd, L., Clemente, C.J., Giannakis, E., Hodgson, W.C., 
Luz, S., Martelli, P., Krishnasamy, K., Kochva, E., Kwok, H.F., Scanlon, D., 
Karas, J., Citron, D.M., Goldstein, E.J.C., Mcnaughtan, J.E., and Norman, J. 
2009. A Central role for Venom in Predation by Varanus komodoensis (Komodo 
Dragon) and the Extinct Giant Varanus
06