Strictly speaking the orthodox have always believed animals do not have immortal souls. They have a spirit which animates all life, but that spirit is not an immortal soul. So unlike us, when any animal dies, they cease to exist. Neither do animals have a free-will to choose or reject God. So if any animals did go to Heaven, it could not be based on a judgement of the life of any particular animal.However, some have speculated that many, many things which give us great pleasure in this life COULD be a part of the next, including the love and joy experienced with some of our pets/animals. So this speculation suggests that because in our walk towards God, the Christian life naturally draw others (human) along with us, that same draw could pull (as opposed to "draw"- helping lead other rational beings) our dearest pets along with us. The idea God could recreate a non-rational soul and reanimate that life for us, for our joy is not contrary to God's Nature or beyond His Abilities. And if the idea as presented is not God rewarding an animal for anything, but it is a part of rewarding the owner, there seems nothing wrong with the justification of it.Yellowstar, a "Travelers Guide to Heaven" is a short read and one of the minor topics addressed is this very idea. The strongest objection is perhaps that such joy (from our pets) is meaningless next to what Jesus describes as indescribable. To which one could respond how do you know what would be bring me great joy in the next life and perhaps you have never felt the joy of the relationship with a pet as I have. I do not think as a blanket statement if it is true that some pets go to Heaven, that everyone will have all their pets in Heaven. Not everyone likes animals the same way some do. I think we have every reason to believe God knows our hearts, including that which brings each of us our greatest joys, and that He has prepared a place that is special for (and to) everyone going there. In that sense Heaven must be individualized for us to some degree. I see nothing wrong with the idea that our gaining reward in Heaven could bring some of our pets with us. As to Hell, the idea of Hell seems to me to be a solo journey, the path to get there is all about self, a personal journey that does not include others. Am not sure the reward for selfishness should include others, even animals. And there is nothing fitting with punishing a non-rational animal for the rational choices of it's owner.