IMHO–neither the catechism, nor the Bible–neither are written for animals. Man is the important one. Why would the Bible or the Catechism devote long sections to the fate of animals in eternity? The only portion in the catechism which seems to concern animals is 2415-2418. These only speak about their role on earth and man’s responsibility and care for them and to them.
The chapter that teaching # 1703 comes from–the chapter is entitled “MAN: THE IMAGE OF GOD”. The whole section is about man. It has nothing to do with animals at all. So how can this be proof that there will be no animals in the afterlife?
Why would God go into a huge scenario about animals or tell us exactly how they were created? He hasn’t done this: so the conclusion has to remain the same: this is a matter of opinion only. The catechism does not give us an exact answer, or even directly speak on this subject, so why be so adamant that there is absolutely no afterlife for them?
God gave life to all. This life belongs to him. When God hasn’t even directly revealed all these things to mankind, who are we, that we know the mind and plan of God so intricately that we can say we know exactly what the afterlife will hold for every single creature that God has ever created?
Thanks for reading my bit