Why Nipples Get Hard in the Cold

Nipples are some of the most fascinating parts of a human's body, for a multitude of reasons. They provide focal points for the chest and an interesting event for the males (and some females) of our species. One of the most pertinent, insisitent questions that mankind has asked about them is simply this: Why do nipples get hard in the cold? This phenomenon is observed almost universally across the spectrum of mammalian creatures. The fact that nipples scrunch up and get hard in the cold has proved to be a most fascinating one for our species in particular.

Nipples

Before we move on to our explanation of exactly why do nipples get hard in the cold, it would only seem appropriate to provide a short explanation on what nipples actually are. If this bores you, you may skip ahead to the next section "Why nipples get hard in the cold". The nipple is a small protrusion of skin located on the ventral surface of all mammals. The typical nipple contains between 15 and 20 lactation ducts, arranged around the point. The nipple is one of the most nerve rich areas in the body, making them incredibly sensitive. The nipples function as a vehicle for providing milk to offspring and in humans, to attract mates.

Why nipples get hard in the cold

The reason why nipples get hard in the cold is because they are trying to preserve heat. When a nipple is exposed to cold temperature skin reflexively contracts, causing the nipple to become smaller, wrinkled and "hard." The ultimate function of this reflex is to decrease the amount of surface area on the nipple that is exposed to the cold. This decreases the amount of body heat that is lost to the cold and ultimately the amount of energy it takes to sustain homestasis (keeping normal body temperature) in an organism. So decreasing surface area is the ultimate reason why nipples get hard in the cold.

Besides getting hard in the cold, nipples will also become hard when stimulated, or when their owners are sexually stimulated.

Some women actually experience mild pain when their nipples are very hard, because of how strong the skin contracts.

Contrary to proper belief the "hardening" of nipples in the cold is not caused by erectile muscle, but rather by simple contraction of smooth muscle. The process is most similar to that of a hair follicle standing up on end.