Now, I won't tell you what stance I took- I'm just interested, what do you think?
Couple of arguments:
Paul says in Romans- death entered by Adam. So, that means all death, even death at the cellular level. So, animals didn't die either.
Counter argument: Cats (such as my cat Eleanor Aquinas) and other animals have fangs- so they were built to kill. So there must have been death in terms of animals (though of course not humans!) before the fall.
Also, Luther, Gerhard, and Aquinas all agree that a unique part of the imago dei is that fact that human were deathless- that is, immortal like God. Now, since animals are not made in the imago dei, then of course they would die.
Lastly, it is not certain that Paul means death for all creation, since he says death entered through sin- but of course animals don't sin (as far as we know!).
So, put in your two cents- I'd be interested in what argument you buy more.