Re: Planet Dinosaur Ep 2

[Dann Pigdon <dannj@alphalink.com.au>]

On Fri, Sep 30th, 2011 at 6:17 AM, "Richard W. Travsky" <rtravsky@uwyo.edu> 
wrote:

> On Thu, 29 Sep 2011, Tim Williams wrote:
> > Having said that, having a pair of sickle-claws stuck in the flanks of
> > your prey would have the potential to inflict a great deal of damage -
> > especially as the prey struggled.
> 
> Would that not put a lot of stress on the claws and foot (and leg)? All
> that thrashing while "connected"?

Indeed - the typical velociraptorine ungual is extremely narrow laterally, and 
I see no reason why 
those general proportions wouldn't also apply to the living claw with a keratin 
sheath. Judging by 
their general proportions, I had always imagined they would have been poor at 
standing up to any 
force that wasn't delivered straight down the long axis of the claw (such as 
twisting or sideways 
sheering forces). My general assumption seems to have been borne out by actual 
biomechanical 
studies (Manning et al 2009 - www.manchester.ac.uk/escholar/uk-ac-man-scw:45585 
).

This may suggest that velociraptorine unguals would have been better suited to 
the sort of hit-and-
run predatory tactics seem in poisonous snakes or great white sharks. A series 
of quick plunging 
attacks with the foot claws followed by a rapid retreat to evaluate the 
situation. Eventually the prey 
might have succombed to either shock or blood loss from the repreated strikes, 
with a minimum of 
risk to the dromaeosaur in question. This is pretty much the tactic employed by 
secretary birds 
against snakes.

-- 
_____________________________________________________________

Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
_____________________________________________________________