# Why do nipples get hard when someone is cold? **URL:** \ **Category:** Factual Questions\ **Created:** [October 13, 2005, 4:32pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088 "2005-10-13T16:32:11Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![cat39645](https://avatars.discourse-cdn.com/v4/letter/c/c37758/32.png) [@cat39645](https://boards.straightdope.com/u/cat39645)\ **Post date:** [October 13, 2005, 4:32pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/1 "2005-10-13T16:32:11Z")
Why do nipples get hard when someone is cold? ---
**Author:** ![Skott](https://avatars.discourse-cdn.com/v4/letter/s/b4bc9f/32.png) [@Skott](https://boards.straightdope.com/u/Skott)\ **Post date:** [October 13, 2005, 5:42pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/2 "2005-10-13T17:42:38Z")
Same reason you get goosebumps? ---
**Author:** ![ltfire](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@ltfire](https://boards.straightdope.com/u/ltfire)\ **Post date:** [October 13, 2005, 11:44pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/3 "2005-10-13T23:44:08Z")
And, how come your dick does the opposite? ---
**Author:** ![Anaamika](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@Anaamika](https://boards.straightdope.com/u/Anaamika)\ **Post date:** [October 13, 2005, 11:49pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/4 "2005-10-13T23:49:07Z")
Hmm. I was going to say “erectile tissue”, but [Wikipedia](http://en.wikipedia.org/wiki/Erectile_tissue) says no with no further explanation. Anyone know? [Here’s](http://en.wikipedia.org/wiki/Nipples) more info but still nothing definitive. ---
**Author:** ![Anaamika](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@Anaamika](https://boards.straightdope.com/u/Anaamika)\ **Post date:** [October 13, 2005, 11:50pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/5 "2005-10-13T23:50:53Z")
Here’s more: > [@](#): > > The nipple and areola are located near the center of each breast. They most often have a color and texture that is different from that of the surrounding skin. Their color varies from very pale pink to black, and darkens during pregnancy and lactation. Their texture can vary between very smooth to wrinkled and bumpy. The nipple usually projects outward from the surface of the breast. The areola is the like pigmented area surrounding the nipple. The size of both varies considerably from woman to woman, and some size variation is normal from breast to breast on the same women. **The nipple and areola are composed of smooth muscle fibers and a dense network of nerve endings. The nipples become erect as the result of muscular contractions, not blood engorgement.** From: [http://www.the-clitoris.com/f\_html/fr\_index.htm](http://www.the-clitoris.com/f_html/fr_index.htm) (bolding mine) ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 14, 2005, 12:08am UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/6 "2005-10-14T00:08:18Z")
> [@Anaamika](#): > > Hmm. I was going to say “erectile tissue”, but [Wikipedia](http://en.wikipedia.org/wiki/Erectile_tissue) says no with no further explanation. Anyone know? If you click on the [nipples](http://en.wikipedia.org/wiki/Nipples) link in that article, you get a whole article on nipples which says, in part: > [@](#): > > Stimulation or sexual arousal can cause the nipples to become erect. Breastfeeding or exposure to cold temperatures often have this effect as well. Pregnancy and nursing tend to increase nipple size somewhat, and this increase may remain permanently thereafter. Small non-striated myocytes (muscle cells) arranged cylindrically within the nipple are responsible for this erection of the nipples. These muscles are in place to cause the nipple to become erect during breastfeeding. As a side effect, cold also causes them to contract in a similar manner to the tiny muscles attached to your body hairs, which is what causes “goosebumps” in the cold. It is the contraction of these muscles which causes the nipple to become erect. ---
**Author:** ![Anaamika](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@Anaamika](https://boards.straightdope.com/u/Anaamika)\ **Post date:** [October 14, 2005, 12:20am UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/7 "2005-10-14T00:20:03Z")
> [@Q.E.D.](#): > > If you click on the [nipples](http://en.wikipedia.org/wiki/Nipples) link in that article, you get a whole article on nipples which says, in part: That’s what the second link in my first post leads to. > [@](#): > > These muscles are in place to cause the nipple to become erect during breastfeeding. As a side effect, cold also causes them to contract in a similar manner to the tiny muscles attached to your body hairs, which is what causes “goosebumps” in the cold. It is the contraction of these muscles which causes the nipple to become erect. Isn’t that what my other post says?? But thank you all the same. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 14, 2005, 12:32am UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/8 "2005-10-14T00:32:45Z")
> [@Anaamika](#): > > Isn’t that what my other post says?? Yes, but obviously it wasn’t there when I was posting. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [October 14, 2005, 3:09am UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/9 "2005-10-14T03:09:54Z")
> [@Q.E.D.](#): > > Yes, but obviously it wasn’t there when I was posting. OK, My nipples are erect right now. Why is _that_? It’s not cold where I am. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 14, 2005, 3:15am UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/10 "2005-10-14T03:15:13Z")
> [@Inigo Montoya](#): > > OK, My nipples are erect right now. Why is _that_? It’s not cold where I am. I dunno. Quoting posts makes you horny? 😃 ---
**Author:** ![Amazon\_Floozy\_Goddess](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@Amazon\_Floozy\_Goddess](https://boards.straightdope.com/u/Amazon_Floozy_Goddess)\ **Post date:** [October 14, 2005, 4:51am UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/11 "2005-10-14T04:51:48Z")
> [@Q.E.D.](#): > > I dunno. Quoting posts makes you horny? 😃 Makes _me_ horny. Heh heh heh…you said “nipples”. Heh heh m heh. ---
**Author:** ![Anaamika](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@Anaamika](https://boards.straightdope.com/u/Anaamika)\ **Post date:** [October 14, 2005, 1:13pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/12 "2005-10-14T13:13:16Z")
> [@Q.E.D.](#): > > Yes, but obviously it wasn’t there when I was posting. Oh. Right. _slinks away_ ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [October 14, 2005, 1:56pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/13 "2005-10-14T13:56:02Z")
Well, I’m not clear on exactly why temperature changes should affect the nipples, particlularly since I’ve noticed that MY nipples get hard when I’m in a very hot shower. What’s up with THAT? What is the mechanism that leads to that condition? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 14, 2005, 5:23pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/14 "2005-10-14T17:23:59Z")
Probably stimulation in general does it. As for the male bits, the scrotum shrinks when it’s cold as part of the temperature regulation system for the testicles. The testicles function best in a narrow range of temperatures, a little below body temperature (which is why they hang outside in the first place). When it’s hot out, they need to hang further from the body to be at that temperature, so the scrotum extends. When it’s cold, they need a little more body heat, so the scrotum contracts to pull them in. To the extent there’s any effect on the penis, it’s just going along for the ride. ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [October 14, 2005, 5:36pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/15 "2005-10-14T17:36:00Z")
Well, yes, but I guess I’m asking what the mechanism is. Stimulation leads to muscular contraction? And for what evolutionary purposes could this be? Perhaps it increases the sensitivity in females and makes them more inclined to engage in intercourse? I wonder. FWIW, I am a male. So whatever the mechanism and purpose, in me it evokes the old question of why men have nipples, and makes me think it’s one of those parallel constructions that males happen to carry but that is functional in females. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 14, 2005, 7:39pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/16 "2005-10-14T19:39:19Z")
> [@](#): > > And for what evolutionary purposes could this be? Perhaps it increases the sensitivity in females and makes them more inclined to engage in intercourse? No, no, you’ve got to remember the _other_ purpose of breasts, here. The primary cause of nipple stimulation would be a baby attempting to suckle. And that baby will have an easier time of it if he has a nice protruding nipple to latch his lips onto. So when the nipples are stimulated, they respond by becoming suitable for nursing. The reaction in males, of course, is just evolutionary sloppiness, like the existance of male nipples in the first place (it’s easier for an organism to exist with similar male and female structures). ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [October 14, 2005, 7:50pm UTC](https://boards.straightdope.com/t/why-do-nipples-get-hard-when-someone-is-cold/326088/17 "2005-10-14T19:50:35Z")
Ah, yes. Suckling. That must be part of the story. But sexual arousal leads to erection as well. There might also be increased sensitivity to touch when nipples are erect, which would support my hypothesis - that nipple erections would tend to lead to continued sexual activity, e.g. intercourse.