How should we treat animals?
Animals are our fellow creatures, which we should care for and in which we should delight, just as God delights in their existence.
Anuimals, too, are sentient creatures of God. It is a sin to torture them, to allow them to suffer, or to kill them uselessly. Nevertheless, man may not place love of animals above love of man.
(from the Catholic Youth Catechism question 437)