My best guess here is that the animals are being banished because they ate forbidden vegetables and nuts. But is this possible to figure out without the throwaway panel showing the ferrety-looking creature eating a carrot? Otherwise we just see a squirrel eating an acorn, which itself isn’t enough to show a pattern.

And if this is the correct interpretation (which of course it might not be), what in God’s name were the animals supposed to have eaten?

Just as an aside, I’ve always been impressed that the Tree of Knowledge taught Adam and Eve that they had different naughty bits they needed to cover.