I've read about a folk tale that explains why are dogs noses are cold and wet.
It is said that when God flooded the earth, Noah and two of everything living at the time were floating around for a long time (except for the unicorns who were too busy playing to come when Noah called them.) During this time, the two dogs that Noah had chosen constantly patrolled the ark, checking up on the other animals, the people and generally just "policing the perimeter," I guess. On one of their trips around the ark, one of the dogs (probably the female!) noticed a small leak in the ark through which water was gushing and threatening to eventually sink the ark!
While the second dog ran for Noah, the first dog--being resourceful like most females are--stuck her nose in the hole to plug it until help could arrive. By the time Noah and the other menfolk arrived, the poor whole-plugging dog was in a terrible state--in pain and gasping for breath! But, through her selfless act, she had saved the world!
It is said that God caused all dogs from then on to have cold, wet noses so all the world would forever know and be reminded of how one dog's great bravery saved the world!
These noses would make good plugs, wouldn't they?