I think about Rudolph Steiner's work on Karma. He talks about that when we split off from the animals into the human being the animals took the responsibility of our karma since the human was going to be so destructive to this world and many even destroy it. The Grass eating animals take up our physical karma, the birds our mental karma and we can see how out of balance and critical this world is, we have too many humans and very less animals to clear up this karma these days.
It is highly important for us to keep ourselves balanced and straight.