The article has some anecdotes of past attempts at animal-based warfare:
WWII: Attach a bomb to a cat and drop it from a dive-bomber on to Nazi ships. The cat, hating water, will "wrangle" itself on to enemy ship's deck. In tests cats became unconscious in mid-airIt looks like the U.S. military's Tierekrieg strategies have a poor track record.
EDIT: Predictably, there's some great commentary over at Pharyngula.