Animals are creatures of the earth. Everything God made is "very good", according to Genesis. Unless we are to assume that God made a mistake (which is impossible, because God is perfect and holy), we should assume what God does will last. Animals were one thing God did. Not natural selection evolution. So, we can therefore conclude that God did a great thing in making all creatures: man and animals and the holy angels. Holy men and women and children will be in heaven. Made holy by God's mercy and grace, as all are born and formed in sins, and all have sinned. In the next world, there should be whatever is good from the present world. It isn't something we can necessarily be dogmatic about, but it doesn't make sense that God would make animals and then change His mind about them. There was a good reason He made them. To give glory to Himself. Most of all, Man was created to love, know, and worship God, and give God alone all the worship and glory. As for animals, they will join with man in the worship of God the Creator in the new world (age) to come. And the holy angels will be there too.
The devil and his angels will be destroyed, taken away from the universe, and the people who didn't repent and receive Christ will not be in the blessed world to come.
These are my thoughts on this.
God bless you Katy-follower. In Erie Scotth1960