Although it is not a particularly hard-fought discussion, and you are unlikely to see it in the newspapers or on television, among High Fantasy books lovers there is a statement that most of them adhere to: that the dragons shown in movies and on television are not really dragons, but rather wyverns.
Wyvern? What is that?
The wyvern (in Spanish, guiverno) is a mythological animal of the late Middle Ages and later centuries, mainly associated with heraldry, similar in every way to the dragon, although with the notorious variant that, instead of four, it has two legs or sometimes none at all.
Strictly speaking, the purists are right. The modern conception of the dragon corresponds to a quadrupedal animal whose wings emerge from a point not always determined on its back, mostly from an extension of its scapulae in the case of the western species, or without them in the case of eastern dragons. This is how, for example, it was depicted in the 1996 film «Dragonheart».
Nevertheless, we have seen that in almost all recent mega-productions («Game of Thrones», «Harry Potter» and Peter Jackson’s film adaptations of «The Hobbit») the dragon is depicted with two hind limbs and wings emerging from its forelimbs, giving the impression that it has only two legs.
It is likely that the change originated (urged on by films increasingly concerned with their pretension of realism) in the need to give credibility to the dragon image, imitating the forms assumed by the species that evolution successfully endowed with wings: pterosaurs, birds and bats.
However, in the opinion of this writer, there is no reason to make this distinction. The use of the word wyvern dates back to the 13th century, and before that the word dragon was used interchangeably to indicate creatures with four or two wings, even without any, and if we go back to the etymological origin of that word, we will see that, ultimately, draco refers to a snake; on the other hand, wyvern comes from the terms wivre, guivre and vouivre, all of French origin, and these from the Latin vipera, that is, viper or snake.
In fact, as attested by the illustrations of various medieval treatises, the bipedal dragon was once much more common than the quadruped, and the beast assumed various forms; and since the serpent and the dragon are so closely linked by symbolism, it is not surprising that they are confused in the artistic representations that abound throughout the history of art. In this sense, mythological creatures such as the griffin, the basilisk, the tarasca or the chimera owe much to the figure of the dragon and are more closely linked to it than most people imagine.