> Senter (2005) proposed on biomechanical grounds that the forelimbs
> of _Mononykus_ were well adapted to scratch-digging or
> hook-and-pull movements, and so proposed that alvarezsaurs used
> their findlimbs to open tough insect nests, in the manner of
> anteaters and pangolins.
A problem I have with this hypothesis is that the extreme shortening
and monodactyly separates these members from the condition in
currently known large mammalian anteaters.
> I don't mean to contradict this - but it's possible that the
> alvarezsaur forelimb morphology lent itself to other functions too.
> Such as picking off parasites from large hosts - or cutting through
> the same host's skin as well for a blood-meal (as seems to be the
> case for oxpeckers on ungulate hosts).
In general, picking up prey actions also seem not so fitting with
short forelimbs. In any case, the fused wrist bones suggests a
poverty of manipulative action, and the ventrally facing palms do not
seem good to grasp insects (better would look medially facing ones).
> Or as I suggested many moons ago, alvarezsaurs might have been
> scavengers that used their strong, monodactyl forelimbs to open up
> large dinosaur carcasses.
It may be, although I suspect that dinosaurs with great olfactory
acuity as tyrannosaurids and dromaeosaurids may reach it before and
open the carcasses then. I would also expect more laterally
compressed unguals, dromaeosaur-style, if expecting carcass
hide-cutting.