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> 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.
These mammals are all quadrupeds. Their forelimbs are compromises
between the hook-and-pull function and the locomotory function.
Alvarezsaurids had no need to compromise, and it shows!
> 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