Pellisans were once more common. Due to old superstitions about the Pellisan there are very few Pellisans in the modern era. If you manage to find a Pellisan egg count yourself lucky.
Several hundred years ago, back when Ark was divided into kingdoms, the appearance of a Pellisan was considered a bad omen and a sign of the imminent failure of the kingdom where it was sighted. Each kingdom would have specialized knights who's duty it was to seek out Pellisans and destroy them, and in some cases a Pellisan would be quietly relocated to a different kingdom in order to bring its bad fortune down upon them instead.