Over the years not a few pet-lovers have asked me if they will be reunited with their dead pets in the world of spirits and in the resurrection. To be quite honest, I have struggled with this one. My knowledge - both Scriptural and experiential - has not given me absolutely concrete answers on this question. I couldn't therefore give you a 100% certain answer but hopefully I can share a few insights.
The standard argument against animals being resurrected is that they, unlike human beings, have no 'souls'. I'm afraid, though, that this is rather a meaningless notion because the idea that we 'have' a soul comes from mediaeval Catholic theology, not from the Bible. The Bible nowhere says that we 'have' souls - it says we are souls.
Let me explain without getting too technical. (If you want an exhaustive study, then please read, The Bible Teaching on 'Soul' - also take a look at our Soul Sleeping section). The Hebrew scriptures say that Body + Spirit = Soul. I am a living soul. You are a living soul. When Yahweh blew Ruach (Spirit) into clay, the first man (Adam) became a living soul.
That is what Seventh-Day Adventists, Jehovah's Witnesses, Christadelphians, some Messianics and Herbert Armstrong advocates teach. Unfortunately, it is not that simple as the article, The Bible Teaching on 'Soul', shows. Like English, ancient Hebrew words can mean different things and some words were used interchangeably. Even dead bodies are called 'souls' in the Tanakh (Old Testament). And if that isn't confusing enough, Yahweh Himself is even said to have a soul in one passage. So when it comes to the spiritual makeup of man and animals it is impossible to be dogmatic because there isn't enough data on the subject.
I have my own belief about this which you can read about in the article.
Now to experience. I once had a beloved dog when I was a boy called Josephine. When she died I was devastated. Many years later I became a believer and a short while afterwards I saw a vision of her in the spirit world. She sensed my awareness of her and was happily wagging her tail in recognition. At that moment I knew that she was alive and well in the spirit and that one day we would be reunited. When it comes to animals, that is about the only think I can say with certainty. I have since seen another pet dog, Vivaldi, running around in a heavenly garden. He was a cripple toward the end of his life and was enjoying the freedom on his new spiritual home.
Will all animals be resurrected? What about plants and bacteria? Heaven and the resurrection are states of perfection so I find it hard to believe that animals such as parasites (e.g. tapeworms or mosquitoes) will have any function in a perfect world, but that's just my opinion. Having seen the world of spirits on a number of occasions in vision I can confirm that there is some sort of plant life - the Bible mentions trees though the ones spoken of do not seem to resemble anything like the types we have here. Other animals I did not see but then I was not looking for them, my attention being on the people I saw.
Maybe the plants and animals that are resurrected will be those that we loved and are filled with a part of us because we carried them in our hearts, but maybe that is just a na´ve and sentimental (if not vain) view of things. Whatever Yahweh has will be far greater than we ever dreamed of or could ever imagine. I believe He is love, justice and goodness. He loves the nature He created, at least, the pre-Fall version of it. He loves life of every kind and so I can only imagine that heaven and the resurrection will be jam-packed with it. Whether it will be entirely new or whether it will be restored (resurrected) life forms from this world, or both, I can only guess. One thing I am sure of is that it will be good and that no love we have ever had for any person or creature will ever be diminished or removed. The eternities are vast so I am sure they will even include the inanimate things we loved down here like mountains and lakes. Lakes I know exist, for I have seen them and even bathed in one in my spirit.
Pet-lovers have nothing to be afraid of - whatever we dreamed and hoped for in the goodness of our hearts will be even better than we asked for. So I believe we shall be reunited with the animals we once loved. Absolutely.