Why Do Birds Have White And Dark Meat? (And Do We?)

If you’ve ever been in charge of serving turkey
at Thanksgiving, you may know that birds have both white and dark meat. That’s because they have two main types of
muscle fibers: slow twitch and fast twitch. As you might expect, slow twitch muscle fibers
contract more slowly. They’re built for endurance activities, like long-distance flying, and
they’re full of the protein myoglobin, which is a special kind of nutritious, salty slime
that your muscles have to carry oxygen around. The cells of slow-twitch muscle fibers are
packed with mitochondria, these little organelles that act like power plants. The mitochondria
take in the oxygen from the myoglobin and metabolize it into a really important molecule
called Adenosine Triphosphate, or ATP. ATP is like fuel. It’s the molecule that stores
the energy for living things to do just about everything. And the process of turning oxygen into ATP
is pretty efficient; as long as there’s oxygen available, the mitochondria can keep at it
all day. But it isn’t fast. So birds also have fast twitch muscles, which
are usually at rest, but can burst into action when needed. Fast twitch muscles don’t contain
myoglobin; in fact, they don’t even have mitochondria which means they can’t use oxygen at all. Instead, those muscle fibers produce glycogen,
which is a type of sugar that can be burned in an emergency. Now both myoglobin and mitochondria are pigmented:
myoglobin is red, and mitochondria are brown. So slow twitch muscles look darker, redder,
and browner. Glycogen, on the other hand, is pretty much colorless. So nearly-flightless birds that only ever
fly short distances, like turkeys and chickens, have light-colored, fast twitch muscles in
their breasts and wings. But long distance fliers like ducks or geese
pretty much only have slow twitch muscles. That’s why their meat is dark and gamey. Now the really important question: do YOU
have both dark meat and white meat? The answer is no, sort of. But also kind of
yes, sort of. Most animals have muscles that are either
dark or white. In fish, for example, you’ll usually find white meat because they float;
they don’t really need a lot of muscle power to get around. But some fish like tuna and
salmon have darker meat, because they’re constantly swimming through a current. Mammals, however, are different. Instead of
having some muscles that are slow twitch and some that are fast twitch, almost all of our
muscles contain both kinds of fibers. The concentrations of each kind can vary depending
on where the muscle is and what it does — the muscles in your eyes, for instance, have more
fast-twitch fibers, whereas ones in your back that maintain your posture are primarily slow-twitch. But the combination of the two fibers throughout
your body is why, instead of having brownish muscles and white muscles, you’re nice and
pink all the way through. That’s what we call red meat. I could really
go for a steak right now. Anyway, thanks for watching this Quick Question
— especially to our Subbable subscribers who keep these answers coming. To find out
how you can help support our question-answering endeavors, just go to Subbable.com/SciShow. And if you have a quick question, let us know
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99 thoughts on “Why Do Birds Have White And Dark Meat? (And Do We?)

  1. Did this jackass just say that birds have muscle cells that don't use oxygen? Wow. Less peroxide in the hair and more effort on learning. This metrosexual is nothing more than a talking head.

  2. Me and a Friend we're cycling on a hot day and he got very sweaty and said "why couldn't the earth be a couple thousand miles more away from the sun?" This sparked an argument with me saying we'd die and him saying it would just be cooler… So what would happen to earth if it was a couple thousand miles further away from the sun???

  3. With nutrition guidelines saying like, don't eat red meat, eat white meat instead, does that entail that the presence of myoglobin, mitochondria, or glycogen entail some nutritional value? (Should diabetics avoid eating fish and other white meats due to glycogen?) Is there even a correlation between presence of myoglobin and amount of cholesterol in the meat, or is it just pure coincidence. Does this mean that it's better to eat chicken rather than duck, etc etc etc.

    Dumb, but necessary questions!

  4. How does Helium affect our vocal cords? I watched the video on Helium from 2 years ago but it didn't really touch on this. There are other videos that explain this but I'd like to see Scishow's take..

  5. that was gross and subliminal. I think you just warped some ppl into finding cannibalism 'interesting'. yuch

  6. I've seen tons of meat (that's what she said) from cow, pig, deer, dog (Korean delicacy) and even human, after a bad wreck, and none of it looked like the red dyed meat in the store. Why do people need for it to be so bright red?

  7. Fun fact of the day… ATP is also what causes animals to move after they are dead. Basically the rest of the bodies ATP needs to be used up before it can go into rigor mortis. So next time you think a facility is hanging live animals…you can think again.

  8. When you talked about the muscles in our eyes, I blinked and thereafter manually blinked for about five minutes. Why is it that when someone mentions blinking or breathing, or even reads something to do with it, you start doing it manually.

    I've set myself off again!

  9. The purple background with the green screen use made you turn out very yellow-green in color when watching in full screen on a large monitor.

  10. My cousin asked me how food gets its color, like why cherries are not orange, how and why they become red ? and i was like ….ow aaaa I …aaaa …. how to explain such thing.. sooo yeah that is my question  .. 😀

  11. So, you're saying that read meat is just both kind of fibers (fast and slow twitch). Then, why is it regarded as unhealthy to eat red meat, but white meat is fine?

  12. My question for SciShow: What causes gamey meat? Why does goat always taste gamey, but lamb sometimes not? Grass fed beef can be a bit gamey but not corn fed. Wild game covers the entire spectrum of gamey-ness. Can fowl or seafood taste gamey?

  13. Compeltly unrelated to the topic, but sscishow staff or anybody else in the comments: why can humans freeze? (from cold weather). Aren't we already solid, and there's no phase of matter that's "colder" than solid? Is it just the liquids inside us that are freeizing…? Or…?

  14. nutrition wise- is it better for an athlete to consume protein from myogoblin meat or the mitochondria meat?

  15. My stepbrothers girlfriends granddad died and in their family it was like a tradition to eat part of his body and cremate the rest. How disgusting it that?

  16. Is it true then that dark bird meat is healthier than white? Kind of like dark bread is healthier than white?
    If it is healthier, why? What more nutrients is it dark meat?

  17. Can you do a video on mitochondria (if you haven't already)?
    Someone once told me we need them to produce energy but they aren't actually part of us, like some kind of symbiotic relationship. She was wrong about quite a lot of things though! lol

  18. Maybe this is a dumb question, but if one is colorless and the other is brownish then why is it pink/red when combined? Does a reaction cause a pigment change?

  19. If you have ever hunted quail, you may have noticed that the young quail, which can be larger than their parents, will have white meat for the flight muscles while the parents will have much darker flight muscles. Perhaps the amount of usage helps determine white or dark meat. If there are any turkey or duck hunters out there, maybe they can expand on this. I have heard that squab (young pigeon) is the same.

  20. So now that every time a customer comes into KFC and complains that wings aren't white meat … I'll explain to them that chickens, as they are mostly flightless birds, thus have myoglobin in their breast and wing areas, in loo of mitochondria. Since myoglobin is, for the most part colorless, the meat is a lighter color. Thus, wings are white meat, you asshat.

  21. Michael seems to have the right amount of energy for SCIENCE! While Hank seem like he did a little coke before each of his videos

  22. Kind of surprised you didn't talk about why pigs are apparently the exception to the "mammals have evenly distributed slow twitch and fast twitch" rule. Even more surprised I couldn't find a comment already pointing this out.

  23. I could really go throw that steak in the bin right now.
    I am not a fan of meat, unless it's really thin (and thus not chewy) veal schnitzel, bacon, ham, Italian sausage, or prosciutto. Beef? Pork? Lamb? Turkey? Chicken? I consider those 'dog food', not 'human food'. Too chewy and inedible for me.

    I also eat fish and prawns.

  24. If you, at any given time, can only utilize 50% of your nose (because of sinuses or some other nose deficiency) would the naturally slower air intake cause a person to gain weight over years?

  25. Mitochondria dont turn oxygen into atp. Oxygens used to drive an electron transport chain that in itself creates a H+ gradient which is used by an enzyme which phosphoralizes adp into atp.

  26. Do I have light and dark meat?
    "The answer is no. Sort of. But also kind of yes. Sort of."
    Simplest and most complicated answer I've ever seen.

  27. So are the Mitochondria, and their function, where George Lucas got the "Midichloreans" from in the Star Wars universe?

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