Depends on the animal I suppose, if you have an animal that is used to being around others and being interactive then you should probably have a companion for it, on the other hand if that animal is used to being alone and having human contact only it is ok to do that to. In a previous post someone said their bird was quite content to be alone with only humans around,in a case such as that it's true that a lot of birds and things are quite content with being alone. Animals are precious and do need to be interacted with if you intend on petting it,touching it and handling the animal often. If it is a specific type of animal you just want to keep and it has wild instincts yet,then maybe or maybe not for a companion with it,depends if you want to breed it or not I would think. Just think of the animal like a human,we all want some sort of contact and sometimes we don't and prefer the solitude.