B2 High-Intermediate US 2055 Folder Collection
After playing the video, you can click or select the word to look it up in the dictionary.
Report Subtitle Errors
[bird chirp]
Look down. No matter what your biological sex, I'm willing to bet most of you have
two nipples. If you can't see them, they're probably under your shirt.
Some people have even more than two! But that's for another video.
It's easy to see why females have two nipples.
We're mammals. It's right there in the name.
Dogs, cats, pigs and whales all have nipples too. Like us, they nourish their offspring with milk.
Male nipples?
Not much going on there.
If they're not an evolutionary advantage, why hasn't natural selection erased them?
Because my nipples are cheap, and they're not hurting anything.
In the eyes of evolution, male nipples don't have much cost: Just a little more tissue.
But deleting them from the recipe altogether, reprogramming the genes and body development
in just in one sex? That would cost more.
Traits don't have to provide a specific advantage to get passed on.
Why is your blood red and an octopus's is blue? It's not because one color's better,
it's just a side effect of nature selecting different chemistry for different creatures.
And sometimes, traits can end up being used for a function
different from what nature originally selected.
Not every trait is an adaptation, and they don't all have a point.
Sometimes they have two.
Stay Curious.
This video's part of our 12 Days Evolution series.
Check out more by exploring Darwin' beard.
Find the links down description or you could click that things that just pop up on screen.
You know what else doesn't cost much? Click and subscribe.
It's free actually.
    You must  Log in  to get the function.
Tip: Click on the article or the word in the subtitle to get translation quickly!


Why Do Men Have Nipples? - 12 Days of Evolution #7

2055 Folder Collection
Tiffany Yu published on December 9, 2018    Tiffany Yu translated    Evangeline reviewed
More Recommended Videos
  1. 1. Search word

    Select word on the caption to look it up in the dictionary!

  2. 2. Repeat single sentence

    Repeat the same sentence to enhance listening ability

  3. 3. Shortcut


  4. 4. Close caption

    Close the English caption

  5. 5. Embed

    Embed the video to your blog

  6. 6. Unfold

    Hide right panel

  1. Listening Quiz

    Listening Quiz!

  1. Click to open your notebook

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯,不妨使用「俚語字典」,或許會讓你有滿意的答案喔