User blog comment:DatDragonRider101/Night Fury Subspecies? - Sand Wraith\Desert Wraith, Wooly Howl/@comment-26219548-20150829115516/@comment-5690373-20150902203945

Even if you don't want to believe in evolution IRL, it is still canon in the HTTYD world. This is from the Seashocker's draagonpedia desription:

Perhaps this is the reason why all dragons fear the a Seashocker's closest evolutionary relative - the electric eel!