Along the line of the dead animal skins, here is another question:
The Bible tells us that Abel was a shepherd, yet humans did not
eat meat until after the flood. What was he doing with all those
sheep? (wink, wink, nudge, nudge)
Also, when he sacrificed, he killed a sheep and offered up the fatty parts.
Did he just wast the rest of the sheep?
And, since there were only four people alive on the earth at the time, it
seems a little strange that Abel would spend all of his time playing with
his pet sheep, while Cain was out working on the farm.