The first wyvern's broke free from what was Zipacna's many teeth. They are the most common dragon, and are sometimes called 'scaled eagles' which is an apt description of them. Comparatively, wyvern's have longer and more flexible necks than eagles, as well as a longer beak-like snout. Their feet and talons are also large, which enables wyvern's to attach themselves to either tree bark or stone. Wyvern's prefer to live in forests. Because of how plentiful they are, if you see a wyvern enter a cave, rest assured that there will be many others there as well.