11 Amazing Facts About the Nipple

The human body is an amazing thing. For each one of us, it's the most intimate object we know. And yet most of us don't know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

Despite its relatively small size on the human body, the nipple gets a lot of attention. Biologically, the nipple serves two key functions: In women, nipples deliver milk out of the ducts within the breast to babies, and for women and men, they serve as erogenous zones. Check out our list of fascinating facts about this often-misunderstood body part.

1. THE NIPPLE HAS ITS OWN SWEAT GLANDS.

The nipple is the raised bump or protrusion on top of the breast that sits on the circular area known as the areola. The areola is often much larger in circumference than the actual nipple, as it holds small sweat glands called Montgomery glands (named for William Fetherstone Montgomery, an Irish obstetrician who first described them). The sole function of these glands is to secrete fluids during breastfeeding to lubricate the nipple and to produce a scent that attracts the baby to its mother's breast.

2. NIPPLES CAN POKE IN OR OUT.

Not all nipples point jauntily outward. Men's and women's nipples can be inverted, essentially pointing inward. In the worst-case scenario, "the skin adheres to itself and has to peel open to [turn outward] initially, and [that] can be painful," Constance Chen, a board-certified plastic surgeon and clinical assistant professor of plastic surgery at Weill Cornell Medical College in New York, tells Mental Floss. For most women, however, an inverted nipple causes neither pain nor prevents breastfeeding with proper technique or nipple shields.

3. SOME PEOPLE HAVE EXTRA NIPPLES.

While most people have two nipples, one atop each breast (yes, both women and men have breasts), some people have extra or "supernumerary" nipples outside of the typical location. One Indian man was even found to have seven.

Leigh Anne O'Connor, a certified lactation consultant in New York, says these extra nipples can appear on or below an area named the Tail of Spence (after Scottish surgeon James Spence), which extends from the breast up into the armpit.

"Some people have nipples in their armpits, or even tiny breasts, and these nipples may leak," O'Connor tells Mental Floss. But an extra nipple is just an extra nipple—no cause for alarm or shame.

4. HERE'S WHY MEN HAVE NIPPLES.

Since the main purpose of nipples is breastfeeding babies, and male breasts do not lactate, it begs the question: Why do men have nipples? Scientists Stephen Jay Gould and Richard C. Lewontin tried to get to the bottom of this conundrum in a seminal paper in 1993.

All human embryos start out essentially the same. If the embryo has XY chromosomes, a gene on the Y chromosome called SRY will activate within a couple weeks of conception and begin to differentiate the embryo into one with male genitals.

However, it turns out that breast tissue begins to develop before SRY kicks in, and since nipples in men essentially do no harm, Gould and Lewontin argue, there has simply never been a good enough reason—evolutionarily speaking—to do away with them. They linger because they're benign. Or as Andrew M. Simons, a professor of biology at Carleton University in Ottawa, Ontario wrote in Scientific American, "The presence of nipples in male mammals is a genetic architectural by-product of nipples in females. So, why do men have nipples? Because females do."

5. THE WORLD'S STRONGEST NIPPLES BELONG TO THE GREAT NIPPULINI.

Who needs pecs when you have nipples like those of The Great Nippulini, a.k.a. Sage Werbock, a performer who makes a living demonstrating the mighty power of his nipples? Each nipple can lift 70 pounds, and he holds a Guinness record for the heaviest vehicle pulled by nipples for 20 meters (66 feet)—988.5 kilograms (2179.27 pounds). He has also lifted a variety of dumbbells, anvils, and bowling balls.

6. THEY'RE VERY SENSITIVE TO STIMULATION.

It's no secret that many people take sexual pleasure from nipple stimulation. However, Michael Reitano, an expert in sexual health and wellness at Roman Health in New York, brings up a study published in 2011 in which researchers set out to map the neurology of sexual stimulation in women. Through MRI imaging, they determined that "when [the nipple is] stimulated, the sensations travel to the same part of the brain that is stimulated when the clitoris, vagina, or cervix is stimulated," Reitano says. The study, published in the Journal of Sexual Medicine, also confirmed that it was possible for some women to have an orgasm by nipple stimulation alone.

While the same brain mapping has not yet been done on men, "there is every reason to believe that it has some capacity to function as a source of sexual pleasure for men as well," Reitano tells Mental Floss.

7. NIPPLES ARE AS UNIQUE AS FINGERPRINTS.

Nipples come in many colors, including pale pink, reddish-beige, brown, and black. Your own two nipples can even vary from each other, as can the areolae. "They also come in many different shapes," O'Connor says. "Some are more flat, while others can be quite bulbous. A person can have two nipples that look very different from each other. Asymmetry is normal."

8. A SPECIFIC KIND OF BREAST CANCER TARGETS THE NIPPLE.

While most forms of breast cancer affect the whole breast, Paget disease of the breast is a rare cancer that targets the skin and ducts of the nipple. "Most patients get a rash on the nipples that looks like a severe case of eczema. It is a cancer of breast epithelial (skin) cells," Chen says. Paget disease of the breast represents between 0.5 and 5 percent of all breast cancers.

9. AFTER MASTECTOMY, NIPPLE SENSATION CAN OCCASIONALLY BE RESTORED.

In breast cancer cases where mastectomy—removal of the breast—is necessary, it is sometimes possible to spare the nipple, allowing for a more realistic post-treatment reconstruction, though sensation is often lost. However, Chen says that in certain cases, "it is possible to restore sensation to the nipples with nerve repairs and nerve grafts when a woman undergoes natural tissue breast reconstruction. Sensory restoration to the nipple after mastectomy is very cutting edge, but if you find the right surgeon, it is possible."

10. NIPPLE STIMULATION CAN HELP INDUCE LABOR IN PREGNANT WOMEN.

When a woman is ready to give birth but the baby isn't, one piece of often-shared advice is to stimulate the mother's nipples to induce labor. A 2005 analysis of six trial studies found a significant decrease in the number of women who hadn't gone into labor after 72 hours. Just under 63 percent of the women who received stimulation were not in labor versus 94 percent who hadn't received it.

The mechanism isn't entirely clear, but breast stimulation causes the uterus to contract. It may also help release the hormone oxytocin, which can start contractions. Once the baby's born, the baby's suckling also has benefits for the mother. "When a newborn suckles, the increased oxytocin causes the uterus to contract [and shrink to its original size over the subsequent weeks] following birth," Reitano explains.

11. BREAST MILK HAS MULTIPLE WAYS TO EXIT THE NIPPLE.

If you've ever pumped your own breast milk or seen it done, you may have noticed that the milk doesn't just come out in a single stream. In a typical nipple, "There are between four and 20 outlets for the milk to come out—it can look like one stream or [coming from] various holes," O'Connor says.

6 Protective Mask Bundles You Can Get On Sale

pinkomelet/iStock via Getty Images Plus
pinkomelet/iStock via Getty Images Plus

Daily life has changed immeasurably since the onset of COVID-19, and one of the ways people have had to adjust is by wearing protective masks out in public places, including in parks and supermarkets. These are an essential part of fighting the spread of the virus, and there are plenty of options for you depending on what you need, whether your situation calls for disposable masks to run quick errands or the more long-lasting KN95 model if you're going to work. Check out some options you can pick up on sale right now.

1. Cotton Face Masks; $20 for 4

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This four-pack of washable cotton face masks comes in tie-dye, kids patterns, and even a series of mustache patterns, so you can do your part to mask germs without also covering your personality.

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2. CE- and FDA-Approved KN95 Mask; $50 for 10

A woman putting on a protective mask.
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You’ve likely heard about the N95 face mask and its important role in keeping frontline workers safe. Now, you can get a similar model for yourself. The KN95 has a dual particle layer, which can protect you from 99 percent of particles in the air and those around you from 70 percent of the particles you exhale. Nose clips and ear straps provide security and comfort, giving you some much-needed peace of mind.

Buy it: $50 for 10 (50 percent off)

3. Three-Ply Masks; $13 for 10

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These three-ply, non-medical, non-woven face masks provide a moisture-proof layer against your face with strong filtering to keep you and everyone around you safe. The middle layer filters non-oily particles in the air and the outer layer works to block visible objects, like droplets.

Buy it: $13 for 10 (50 percent off)

4. Disposable masks; $44 for 50

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If the thought of reusing the same mask from one outing to the next makes you feel uneasy, there’s a disposable option that doesn’t compromise quality; in fact, it uses the same three-layered and non-woven protection as other masks to keep you safe from airborne particles. Each mask in this pack of 50 can be worn safely for up to 10 hours. Once you're done, safely dispose of it and start your next outing with a new one.

Buy it: $44 for 50 (41 percent off)

5. Polyester Masks; $22 for 5

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These masks are a blend of 95 percent polyester and 5 percent spandex, and they work to block particles from spreading in the air. And because they're easily compressed, they can travel with you in your bag or pocket, whether you're going to work or out to the store.

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6. Mask Protector Cases; $15 for 3

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You're going to need to have a stash of masks on hand for the foreseeable future, so it's a good idea to protect the ones you’ve got. This face mask protector case is waterproof and dust-proof to preserve your mask as long as possible.

Buy it: $15 for three (50 percent off)

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Take a Virtual Tour of One of the Quietest Places on Earth

Paul Robinson, Wikimedia Commons // CC BY-SA
Paul Robinson, Wikimedia Commons // CC BY-SA

Orfield Laboratories in Minneapolis, Minnesota, is notable for what it lacks. Inside the anechoic chamber, you won't hear the sounds of traffic, chatter, or even the hum of appliances. The soundproof room is one of the quietest places on Earth, and you can take a virtual tour of the space in the video below.

According to UPROXX, Orfield Laboratories is primarily used for research. The background noise inside the chamber clocks in at -9.4 dBA. For comparison, the quietest place the average person has access to has sound levels closer to 30 dBA. Without any outside noises to interfere, products tested for noise levels inside the space produce extremely accurate results. The room has other purposes as well, such as preparing astronauts for space missions and freaking out tourists willing to pay for a visit.

Experiencing sound levels lower than what's found in nature has odd effects on the human body. Your ears adapt to pick up sounds that are usually inaudible. With nothing else to fill the space, the sounds of your heart, stomach, and even lungs can become deafening. Dizziness, anxiety, and out-of-body-sensations are a few of the reported responses to spending time in the eerily silent chamber.

Though you won't be able to get the full experience from home, you can pop in a pair of headphones and get a taste of what the room is like in this video. The lab is currently closed to visitors, but when it's open it offers tours starting at $125 per person.

[h/t UPROXX]