00:00:00 - 00:00:59
Human nipples vary in size, but new research finds the size, shape, and even sensitivity of your nipples may explain more about you than you think. When it comes to nipple size, studies show male nipples are 36% smaller than female nipples, and on average, male nipples are more similar in size compared to female nipples, which vary in size more widely across human women. This scientific male-female nipple research ended up breaking the field of evolutionary biology. Researchers used to think that when a biological feature
00:00:29 - 00:01:27
on a human more specific purpose, it led to a stronger evolutionary selection, and therefore more similar sizing within or on the human body. But, when it comes to nipple size, female nipples are functional and serve a specific purpose of breastfeeding. Male nipples, on the other hand, are seemingly non-functional. And since these new studies found that functional female nipple sizes vary more than the non-functional male counterparts, it has brought past scientific theories into question. In fact, this nipple research
00:00:59 - 00:01:52
caused evolutionary biologists to rethink a theory that the male orgasm was more functional than the female orgasm. They thought this because male human penises are actually more similar in size compared to female clitorises. Because the penises were more similar in size, they posited that male orgasms and the penis was more functional. This new nipple research brought that all into question. If male nipples are seemingly unfunctional, why do they exist? To start, female humans have nipples because humans are mammals, [music]
00:01:26 - 00:02:21
which by classification means they produce milk for babies, and female nipples are the way humans feed milk to babies. Males, on the other hand, end up with nipples because male and female embryos develop identically for the first four to five weeks in womb. Around week five, the Y chromosome kicks in, and biochemical sex determination factors cause female nipples to prepare for future mammary development, and male nipples, well, well, they just stay there. But, male nipples just stay there cuz from this point forward in
00:01:53 - 00:02:47
development and life, there is no cost. There’s no biological negative energy that comes from these nipples, so they essentially just stick around. Fascinatingly, humans are the only animals that maintain large breasts for life. Female humans have breasts and nipples that change during puberty due to the hormones estrogen and progesterone, which causes an increase in mammary and adipose tissue, making breasts and nipples enlarge for life. In all other animals, including primates, mammary tissue and breast tissue
[U] (also tissues [pl.] ) a collection of cells that form the different parts of humans, animals and plants （人、动植物细胞的）组织
muscle/brain/nerve, etc. tissue
肌肉、大脑、神经等组织
scar tissue
00:02:20 - 00:03:13
enlarges only for pregnancy and lactation. Once the offspring is weaned and no longer needs milk, the breasts disappear, the tissue disappears, and the nipples return to a flatter state. But nipples aren’t always flat. Why do human nipples become erect when stimulated? Nipples have Pacinian corpuscles, which are mechanoreceptors that respond to touch. They are biochemically fascinating because they can transfer physical touch signals into neuronal action. The neurons in the nipple can sense touch, which can flood
00:02:47 - 00:03:43
specific connective tissues with water while signaling smooth muscle tissues to make the nipple pop out. For some, the nipples can become erect upon sexual arousal, is not just in women. A new study found that 50 to 60% of men found that their nipples get hard when they’re turned on. Nipples are considered erogenous zones, with 81.5% of women [music] saying when their nipples are touched, they become aroused. For men, 51.7% claim nipple stimulation increased arousal. But not everyone’s nipples are
00:03:14 - 00:04:10
hardwired for sexuality. 7.4% of women and 10.1% of men claimed that having their nipples stimulated actually decreased arousal. And many other people in the survey said that having their nipples touched did nothing at all to them. But another study found that when men and women have hard nipples, people are more likely to attribute positive traits to them. So, for the most part, in humans, having hard nipples is signaling something good. Nipples also become erect when you are cold or scared due to an autonomic neuronal reflex
00:03:43 - 00:04:37
similar to goosebumps, which causes smooth muscle cells in your nipples to make them pop out. Now, what does your nipple size and shape say about you? Whether you have quarters, dinner plates, pancakes, or pepperonis is most closely linked to your genetics. In fact, one study found that areola color inheritance is similar physiologically to the inheritance of foot size and freckle pattern from your parents. Female nipples vary more in size than male nipples and they fluctuate more often throughout life due to changes in
00:04:09 - 00:05:04
hormones from estrogen and progesterone. Male nipples are more similar in size than female nipples and male nipples on average are 36% smaller than female nipples. 10% of women and 8% of men maintain eroded nipples throughout life, but these nipples are capable of becoming erect when cold, stimulated, stressed, or for breastfeeding. But in general, science has found that all nipple sizes and shapes are normal. But if your nipple changes in size or shape drastically and quickly, it can be a clear indication of an underlying issue
00:04:37 - 00:05:22
or disease and you need to see a doctor. If you want to hear more about our personal relationship to our nipples, mine in fact happen to be very sensitive, Mitch’s are dead. You can click on our podcast where we talk more about our nipples. The side note podcast click where it pops up. Thank you so much for watching. You can like, subscribe, do that YouTube stuff and we will see you soon for a new science video. Peace. Peace.