[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]


On Tue, 20 Feb 1996, Rob Meyerson wrote:

> >> When a part of an animal evolves some kind of offensive purpose, it
> >> usually is for intraspecies combat first.
> Consider horns in pronghorn.  Their primary role is for solving territorial=
>  disputes.  Yet, some future paleontologist could look at the pronghorn=
>  skull and surmise that the horns primarily had an anti-predator function. =
>  Whole senarios would be put together on how the horns would be used to=
>  skewer a predator.  Now, while the horns are occasionally used for this=
>  function, the animal usually chooses too run, showing that this is not the=
>  primary reason why horns evolved.
> I suspect that the club in ankylosaurs are in the same class.  While they=
>  may have had an anti-predator function, the reason why the club evolved was=
>  used primarily for intraspecies disputes.
> Rob

This would be an evolutionary path akin, perhaps, to the quilled tail in 
the porcupine?  The glyptodont's thorny tail?  The housecat's claw?  The 
canine's canine?  What puts the ape in apricot?

I sort of find the >blanket< nature of Rob's theory on evolution of 
offensive weaponry difficult.  I think that the "rules," if you will, are 
a lot less rigidly defined.  I envision tail-swinging disputes between 
ankylosaurs as about as likely as similar contests among porcupines.  
Intra-specific combat usually originates in face-offs, with 
pachycephalosaurs or bighorns the logical conclusion, I'm GUESSING.  

Predators are more likely to approach prey from behind, when the prey is 
fleeing; hence I must persist in my doubt that stegosaur spikes, 
ankylosaur clubs and porcupine quills evolved to settle social issues 
within the respective species.  Rivals approach face to face.  

Many thanks.

John McLoughlin