[Jacob-list] horny question :o)

[Pbs123 at aol.com]

       As far as horn breakage is concerned, I probably should have mentioned 
why curving horns are "better" for head butting than straighter horns (as per 
four horned rams). They relatively and absolutely incur more breakage and the 
explanation lies in the biomechanics of the horn.
       If you strike a relatively straight horn with enough impact to 
fracture it, it initially bends away from the applied force. Just prior to 
breaking, the side opposite the trauma becomes compressed, and the side 
incurring the blow is stretched (placed under great tension). Bone and horn 
are quite effective at resisting compressive forces but don't have as much 
tensile strength, so the horn breaks on the impact side. The further from the 
base the greater the load on the structure and the more likely it is to break.
Horns that curve away from opponents' horns help insure that blows land 
closer to the base. Also, the curved shape subjects more of the horn to 
compression than tension. (Like a geodesic dome?)
       I don't know why horns weep as described. Examining the fluid may 
offer some clues, I'd think. If it's bloody, the origin is probably trauma.  
A "pyogenic" cause (infection) I would think to be pretty obvious as pus 
etc.is readily recognizable. If it's clearish, some kind of edema, it could 
be explained as follows:
       There are a large arteries that serve the horns, which branch (ramify) 
mightily under the horn cores. This interconnected branching, termed 
"anastamosing", insures that via the phenomenon called collateral circulation 
that the horn shouldn't wither and drop off if some of the branches get 
compressed and circulation impeded. Collateral branches will enlarge and 
offer alternative pathways for the blood to take. Only the area being 
compressed should experience necrosis, (in fact it's called pressure 
necrosis) and dying tissue at these sites may account for the fluid. ?
       I know that horns have been observed to drop off during development 
when positioned too closely, but this should not necessarily be the case.

Peter S.
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