NO!!! Don't start about Maia without physical shapes! They are omnipotent!
If we are talking about normal wolves and bats that Morgoth performed his genetic experiments on, then I guess this is a pretty open case. Carcharoth, of course, was a normal wolf 'of the brood' of Drauglin'. He was hand-fed by Morgoth, *mutters about steroids* and ATE a Silmarilli. I guess Huan would not have died fighting Carcharoth without any Silmarilli.
Had anyone draw any comparisons between the Bats and the Eagles? Having read most the works of Prof T, I have always felt that he downplayed the power of Evil, while hiding the power of Good. Yes, its that 'All that is gold does not glitter' thing again. I know this had been brought up before, but that 'Evil cannot conceive' concept felt somewhat hollow, considering that Evil Men can live and reproduce just as well as any other living things, and they were definitely twisted in some sense. (No, I am not about to restart that excellent dedate on Orcish Fear) Personally, I should have more pity for the genetically 'impaired' creatures twisted by Morgoth than those who followed him willingly.