As I was reading the book of Numbers chapter 22 awhile back, I came upon an instance that puzzled me. The verse in question is 28, where God causes a donkey to yell at his own rider, Balaam, after he had beaten his donkey three times.
The verse says that the LORD opened the donkey’s mouth. The key word for me here is “opened.” Before sin entered the world, I believe Adam, and eventually Eve, could talk to animals, which may be why a serpent talking didn’t surprise Eve when she was being tempted. When God opened the mouth of Balaam’s donkey, I believe He removed a barrier that allowed the donkey to speak.
I kept that instance in the back of my mind and have since found many more examples of animals speaking (or understanding words) to convince me that they once had the ability to talk. I also believe one more thing… When it says, “…every tongue confess Jesus Christ is Lord to the glory of God the Father” (Philippians 2:11), it means animals too.
Here are some videos I’ve found that enhances this belief (and for your amusement too):
Cat understands “Why are you doing this?”
Mind@Work 