Violence had begun. Violence that only got worse according to the next couple of chapters. The vegetarian law of Genesis 1 hadn t yet been lifted, so in an ideal world we d expect so. However, the humans had rejected God s laws, the earth was producing thorns and weeds, and so there s really no good reason to expect that the animals weren t participating in the fall. Except that animals were created as animals and as such were above rebellion.
Cows do what cows do.
Sparrows do as sparrows do. And as long as they can be what they were created to be, they can do no wrong. And so, perhaps, the animals in the creation story behaved themselves. In any event, when the ark opened up after the flood, God gave permission for the humans to eat flesh. So, at that point in the story, the animals must have begun putting each other on their menus as well.