I’ve posted this before. It’s a study of Catholic teaching, scripture, and my own (very non-infallible) pious opinion.
Taken from Catholic Answers
All living creatures – angels, humans, animals, plants – have souls. However, there are two kinds of souls: spiritual and material. Angels and humans have spiritual souls. Animals and plants have material souls. Something that is spirit is not subject to the decay of change. Thus, angels do not die and human souls survive the separation of body and soul at death. Material things however are subject to change, thus they are subject to decay and death. As animals and plants have material souls, at death their souls cease to exist.
Whether God will choose to re-create animal and plant souls at the end of time when the material universe is transformed (cf. CCC 1060) is something we do not yet know. However, the Church does not teach that animal and plant souls are “disposable” in the sense that they are of little consequence and can be wasted if humans wish to do so. Animals and plants do not have inherent rights, but humans, because they are appointed by God to be just stewards of nature, have a responsibility to be kind to animals and prudent in using the world’s natural resources. See the Catechism of the Catholic Church:
The seventh commandment enjoins respect for the integrity of creation. Animals, like plants and inanimate beings, are by nature destined for the common good of past, present, and future humanity. Use of the mineral, vegetable, and animal resources of the universe cannot be divorced from respect for moral imperatives. Man’s dominion over inanimate and other living beings granted by the Creator is not absolute; it is limited by concern for the quality of life of his neighbor, including generations to come; it requires a religious respect for the integrity of creation (CCC 2415).
What Spirits Are and What They Aren’t by Frank Sheed
My own Scriptural considerations:
1. Ecclesiastes 3:21 Who knows whether the spirit of man goes upward and the spirit of the beast goes down to the earth?
2. John 11: 25 Jesus said to her, "I am the resurrection and the life; he who believes in me, though he die, yet shall he live,
3. Luke 20:38 Now he is not God of the dead, but of the living; for all live to him.
4. 2nd Peter 3:13 But according to his promise we wait for new heavens and a new earth in which righteousness dwells.
5. Revelation 21: 1**[FONT=Palatino Linotype]* Then I saw a new heaven and a new earth; for the first heaven and the first earth had passed away, and the sea was no more. 2 And I saw the holy city, new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband;
3 and I heard a loud voice from the throne saying, “Behold, the dwelling of God is with men. He will dwell with them, and they shall be his people, and God himself will be with them;
4 he will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning nor crying nor pain any more, for the former things have passed away.”
5 And he who sat upon the throne said, “Behold, I make all things new.” Also he said, “Write this, for these words are trustworthy and true.”***
[/FONT] Since we do not know for sure the end of the souls of animals (#1 above) and we know that Christ stated that he is “the resurrection and the life” (#2 above) and since Our Lord stated that all live to God, (#3 above), then we see twice in the New Testament where Christ promises a new Heaven and earth (#s 4 & 5 above) it seems logical that we may comfort ourselves in our loss of our beloved pet friends with a hope that we will see them again since animals cannot sin it seems more likely that God might resurrect them because of the blessing they have been to us in their lives.
Keep in mind that this is not a teaching of the Catholic Church, or anyone else, but nothing more than my own pious theory.