In the case of dogs and cats that people care for, these are domesticated animals, that do not fit in the natural environments, they depend on human care, and if left to live in the wild they are either killed or upset the environmental balance. They are still being bred, which should not be supported, there is an excess of either animals not still wanted and left for themselves, or taken into captivity, for an interested owner, or killed if there is not any. Those cats and dogs should be saved, and animals for pets should not be chosen right from businesses who have them from breeders. And as there are more needing owners after being caught, and we should not leave more to be in natural environments, spaying and neutering is the right thing and sensible to do for them, with dogs and cats still being cared for.