Because they don't come in green, only kidding, but they are not all brown I have seen many that were pink, my chick has pink ones. But green would be kinda cool just imagine the contrast. Peace
Damn, you put that question in my head and it bounced around all day. Brown or pink (which depends merely on the person's complexion) the question is, why is there a differently colored circle around the nipple? There supposedly are specialized sweat glands on the areola, which I could understand as a smell attractant for the baby, but why the darker color. Do babies seek out nipples visually? There is usually a reason for everything in nature. It's believed that womens breasts are full and round as a butt mimic. Perhaps the different color of the areola is some kind of sexual attractant. I know I find them attractive.
Wikipedia says : The reason the color of the areola differs from that of the rest of the breast is that the areola roughly delineates where the ducts of the mammary glands are.
