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RE: comment-therizinosaurs

What sense does it make that an animal with elongated, tranversely thin unguals 
would use them only for defensive purposes?

There was the idea that they were useful for digging (not usueful at all, being 
thin) or for "hooking" vegetation (which would ask for strong curvature), but 
even so, it makes odd sense to evolve great size, apparent herbivore traits, 
and then large thin unguals not just on the hands but the feet also.

I wonder, but cannot test at the moment, that the unguals were sheathed in 
keratin that did not just copy the shape of the underlying bone, and as such 
_could_ be broader or bear features that make them good at digging or 
destroying earthen structures or for tearing into various objects in general. 
That they are present on the feet, which seemingly would never reasonably be 
involved in defensive posturing, implies that the they (and by this I mean the 
claws in general) were not merely for display and defense.


  Jaime A. Headden
  The Bite Stuff (site v2)

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 

> Date: Mon, 10 Oct 2011 11:52:53 +1100
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: comment-therizinosaurs
> Brian Hathaway <hammeris1@att.net> wrote:
> > "Therizinosaurs also had long forelimbs, and were most likely herbivores" 
> > -- I
> > thought this was a foregone slam-dunk?  With their funky legs they'd have 
> > had a
> > hard time running down or ambushing prey, wouldn't they? They have a weird
> > "look" to be scavengers, too.
> Yes, I'd go along with that. But the long, formidable, scythe-like
> claws that give this group its name look out of place in a herbivore.
> It could be that the forelimbs were used only for defense - such as
> against approaching carnivores. This would make sense because, as you
> say, therizinosaurs would have a hard time running. It could also be
> that the forelimbs were used in predation or scavenging, possibly in
> an opportunistic manner. These critters are truly fascinating.
> Cheers
> Tim