The reason a cat screams after being locked in a cage is because it is not used to living in a cage, so it screams. This condition generally occurs in cats that have not been raised in small cages, so it is best not to keep cats in cages to prevent cats from becoming depressed, angry, etc. If you must keep your cat in a cage, you can put some snacks in the cage for the cat and leave the cage door open so that the cat can slowly eliminate its fear of the cage.