Emu & Mononykus

["Richard L. Dieterle" <Richard.L.Dieterle-1@tc.umn.edu>]

John McLaughlin writes in part: 

"We just dissected an adult male emu, _Dromiceius novaehollandiae_, my first,
courtesy of one of the local emu ranchers.  I was much impressed by the
single talon, a sharply curved keratin-covered hook about 60mm long if
straightened, at the tip of each of the animal's forelimbs. ...   I've been 
watching the rancher's stock closely to see what the big forelimb talon is used 
for, but to no avail so far (but the creatures are penned, so some hook-linked 
behavior may be prevented).  ...  Certainly, the atrophic emu "wing" is a far 
cry from the robust Mononykus forelimb, and the long emu phalangeal hook 
likewise different from the stubby hooflike Mononykus nail, but the question is 
parallel: why does the emu need that long nail?  Why, similarly, the Mononykus 
with its far stouter counterpart?"  

This is an interesting parallel to Mononykus.  It might give us some clues into 
the function of single-nail forelimbs, however different they may be in their 
shape and the shape of their claws.  I wonder if the emu claws are not used in 
mating behavior?  The counter to this is the presumed fact that they are not sex
specific; nevertheless, they might exist in both sexes for the same reason that 
nipples exist in human males.