I've always found it baffling and somewhat amusing that people feel so very strongly that animals won't/don't/can't go to heaven. Really, what does it matter to you if they are there or not? I suppose I can understand that mentality a little bit better in the case of someone who has been terrified or injured by one; however, one thing we can all be assured of is that Heaven will be perfect for us. All hurts and fears, all sin and miscommunication will be wiped away. I don't have access to a concordance or any other research tools at the moment, so from a debate standpoint, I don't have a list of verses to back this up, but I think those things are generally accepted about Heaven.
I grew up with the teaching that animals don't have souls and thus don't go to Heaven. My life has played out in such a way, however, that I have come to see caring for animals, especially abandoned and neglected ones, as part of my God-given calling and purpose in life. As part of that, I have developed some very definite opinions about God and His animal creation. I am not a theologian and don't have profound arguments to back up my theories, but I do have a sense of understanding and peace because of who God is and His relationship to me and the animals He has placed in my care.
Some of my thoughts:
1. With the exception of the serpent, who may or may not actually count as an animal, animals have never been described as sinners in the Bible. Not being created in God's image, they do not have the same moral capacity and responsibility that we do. They are among the part of creation that suffers due to human sin and the curse. Their innocence is why they could be used as sacrificial substitutes for human sin. If they sinned, they would have had to die for their own sin and would not be able to cover ours. Carnivores and scavengers were unclean because of what they ate and how they ate it, but even they weren't said to be sinners. Therefore, I don't see that Jesus death was necessary on their behalf (except insofar as the entire creation had/has to be released from the curse) or that they should have to repent or anything else to be able to enter Heaven.
2. I have come to believe that prior to the flood, humans and animals could communicate much more clearly with each other. There appears to have been a closer bond that ended when God told Noah after the flood that animals would be afraid of humans from then on. (Genesis 9:2-3)
3. God cares deeply and intimately about his animal creation. He knows when a single sparrow falls (Matthew 10:29-30). He nourishes the hungry raven and knows when the mountain goats give birth, he marks the gestation period of the doe, and prepares the desert for the wild o en and donkeys. He knows, and created the ostrich, aware of her habit of leaving her eggs and young unprotected on the sand, and he knows the magnificence of the horse in battle (Job 38:41, 39).
4. When I look at the world around me-its beauty, majesty, intricate detail and design, and I see how animals fit into it and are such a vital part of it, and I realize that Heaven can only be more so, I know without doubt that not only will there be animals in Heaven, there will probably be a wider variety of them than we've ever imagined,and indeed, a host of creatures we can't even fathom here and now. And, if there are animals there, why would He exclude the animals that we know and love? Is He not sovereign and did He not put them in our care for a reason?
There are other, more personal reasons that I see things this way, but I'm content with knowing God, and trusting in the nature of God, and if the animals I have loved and nurtured during their lives on earth are not actually in Heaven, then I'm content knowing that He has them in whatever state or capacity they are now, and that they are loved and at peace. I also believe that as I am His child, and He planted this love of animals in me, He will give me a whole new love and understanding of them when I get to Heaven, and we will enjoy and delight in them together.
We can argue theology all we want, but the truth is, we can't know for sure about the animal issue, and frankly, I don't understand what is at stake for people who fiercely argue that animals won't be there. If they don't want to be around animals in God's presence, I'm sure they won't be, and I'm equally sure that God will enjoy with them whatever passion and calling He made important to them.