Why do dogs have pups but wolves and foxes have cubs?
Dogs have puppies, yes. But what people call the young of foxes and wolves varies. Wolf young are usually called pups as well, at least in literature written by naturalists and scientists. Fox young are sometimes called pups but more often are referred to as kits. They are rarely called cubs. Foxes are not related in any way to cats. Like dogs and wolves (which are not the same species), they are also members of the dog (canid) family. “Kit” is a fairly generic term for a young small mammal.