JCPhoenix:
The best explanation I ever heard or read was this: The reason pets don’t go to heaven is because they wait outside the Gates for us, so when we die they can meet us and we will enter Heaven together. True or not, that though has brought me comfort.
Now, stop laughing at my teary-ness! I know I’m a complete sap!

God has a purpose and some day we will all know the real answer…but for here and now, I know that pets are little blessings given to us to help us cope with the harshness of life outside of the Garden of Eden.
I think you just hit on a real clue about the matter: “I know that pets are little blessings given to us to help us cope with the harshness of life outside of the Garden of Eden.”
If animals are blessings, gifts from God, why would He remove them from us in heaven? What harm would they cause in being there? Especially if they remind us of His glory and goodness.
All creation was called “good.” At least until it fell!
Animals can indeed be BLESSINGS, and often they can teach us lessons that we will accept from them, but not from a person, as their motives are not suspect and they do not threaten our egos the way a person does. The simple loyalty of some animals can teach us much about love. Because they BLESS us in so many ways, perhaps they have a proper place in heaven… just a thought.
I live with parrots, and they exhibit all the range of emotions that humans do, including a sense of humor. Some of them can speak in sentences that THEY have constructed, and exhibit elementary language skills far beyond simple mimicry. They have a commplicated body language, and are able to use tools. They are master manipulators of mechanical devices as well as people!
In Mark 16:15, Jesus says to preach the gospel to every “creature.” (KJV) Some translate it as “to all creation.” (NRSV- Catholic) That would still include the animals. Did not St. Francis preach to the birds? Could it be that we are to preach the gospel to creatures in order to SOOTHE them with the promise of restoration of their “first estate.?” Will THEIR suffering also come to an end, and nature cease to be predatory after the restoration? If the lion lays down with the lamb, it would seem so.
Also, does not the Bible speak of “living creatures” in heaven before the throne of God? Angels? Angels with the form of “creatures?” See Strongs #'s 2937,2938 in the Greek. Also, see Strong’s #2416 in the Hebrew/Chaldee. Also, in Col 1:15, Jesus is called the “firstborn of all creation.” This could imply that ALL creation, man AND creatures, will eventually be glorified in some fashion. The Strong’s word for creation is the same here as in Mark 16:15. If you look up “creature” and “creatures” in Strongs, it is most enlightening!
“Birds, you know, are angels in disguise, come to carry our prayers before the Throne of God.”