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Q:show
eli5: How do parrots copy humans on what they say, how does that work?
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In The Roman Warm period the climate was 2 degrees Celsius warmer than today and is partly credited with Rome success and abundance. Why is returning to a warmer climate considered so dangerous now?
NEWQ:I am not asking this question in bad faith or in an attempt to start a political debate. I was just listening to a Blinkist on the Roman Warm Period and got curious.
CrustalTrudger A:less answers...A first thing to clarify is that the "2 degree C warmer than today" for the Roman Warm Period (or Roman Climatic Optimum as it is also called) is that this is for reconstructed sea surface temperatures (SST) for the Mediterranean, not the temperature on land (e.g., Margaritelli et al, 2020). Generally, elevated SST imply warmer average temperatures, but it's not 1:1 so this is an important clarification. Estimates of the temperature of the Northern Hemisphere more broadly during the Roman Warm Period put average temperatures more around the average temperature of the period between 1960-1990 (e.g., Ljungqvist 2010), so significantly warmer than the periods before and after it, but still cooler than today and less consistently warm than the last few decades (e.g., Luterbacher et al, 2016).
The broader answer to the question though is that global scale proxy records (i.e., various chemical or isotopic records which we can estimate temperature from, often supplemented with global climate models) tend to suggest that most of climate anomalies in the last ~2000 years, whether they were anomalously warm (like the Roman Warm Period or Medieval Warm Period) or anomalously cold (like the Little Ice Age) were local/regional as opposed to global (e.g., Neukom et al, 2019). This is distinct from anthropogenic warming which is a consistent global phenomena. An additional, extremely problematic difference, between these local/regional warm (or cool periods) compared to the anthropogenically driven global warming we are seeing today, is the rate of change. This is highlighted in any number of papers, figures, etc, but is visualized nicely in Figure 3 of Kaufman et al, 2020. The unprecedented rate of warming is arguably as, or perhaps even more, important than the magnitude of warming as this rate is, or will, likely outpace the rate at which ecosystems and human systems can effectively adapt (e.g., Smith et al, 2015).
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Q:
ELI5: Are gas giant planets gassy? As in could I land on a gas giant and like poke my finger through?
CptCap A:less answers...Gas giants are weird.
If you tried to land on a gas giant, you'll first encounter an atmosphere, similar to what you would expect on earth.
It would start very very thin and becomes more substantial as you go down.
As you get deeper the pressure would increase to very high levels, the temperature would rise, then the gas would turn into liquid.
Unlike earth, where the transition between the atmosphere and the ground happens at a very defined point, gas giants transition smoothly. So the atmosphere would become thicker, then soupy-er, until it's basically a liquid.
You would be very dead long before this point, but if you somehow continue to dive deeper, you would encounter another smooth transition, from the liquid mantle made of mostly hydrogen to the solid and rocky core.
and like poke my finger through?
Not really. The atmosphere doesn't start at a set altitude. Vacuum just become less and less void as you get closer to the planet, and there is no point where the change is abrupt enough that it would feel like poking something.
[edit] Many people are asking why we can see gas giants so sharply if their atmospheres doesn't have a clearly defined boundary. This happens because the transition zone from hard vacuum to dense atmosphere, while being several hundred kilometers in height, is very small compared to the overall planet (like a fraction of a % of the radius). The decrease in pressure is also exponential, so only the very lower layers are dense enough to see. You can actually see the fuzzyness in some close up photos. The same is true for earth's atmophere.
tont0r A:Not exactly an eli5, but this is my favorite reddit post ever, which describes what we believe would happen if you tried to land on jupiter.
Ok_Technology838 A:They have a very large gas atmosphere - if you were to fall through this it would start out a fairly sparse atmosphere similar to earth that you’d fall through like earths, then it would get denser and denser, with pressures increasing as you go deeper into the atmosphere, while also getting hotter and hotter. You’d fairly quickly get to a point where you would be crushed by the gas pressure and/or burned to a crisp.
Eventually the pressures get enough that they force th gasses into a liquid state, albeit a very very hot one, and if you keep going deeper they eventually force them into a solid state.
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Why do cars not use transparent fluid hoses? It seems like it would both look cool, and be potentially useful for diagnosis of problems. Are transparent materials simply not robust or hard-wearing enough?
NEWQ:ELI5: Why do cars not use transparent fluid hoses? It seems like it would both look cool, and be potentially useful for diagnosis of problems. Are transparent materials simply not robust or hard-wearing enough?
blahblahsdfsdfsdfsdf A:less answers...Yes, transparent materials are pretty much exclusively fragile or malleable. We could use glass or clear plastic, but glass would be a terrible idea for obvious reasons and plastics expand under pressure. There's research in to pure aluminum oxide as a structural material which is mostly transparent (which is basically
jadesapphire [as pointed out] if I recall) but that would also be quite brittle.For rubber hoses, most of those are made of PVC and get hard and brittle over time, especially when exposed to gasoline or heat.
flyingcircusdog A:Transparent hoses are not strong enough. They look cool in PC builds because they don't need to be that strong, and cost isn't as much of a factor when you're already building a cooled PC.
Car cooling systems are under high pressure and expected to last 10 to 15 years of cycling, so you need stronger materials. The easiest way to diagnose a coolant leak is to look at the surge tank, which is clear for this reason.
LewsTherinTelamon A:It's more or less a rule of materials science that if something is clear then there is a more robust material which is not.
C4Dave A:Back in the old days, the A/C system would have a sight glass about a half-inch in diameter to see if bubbles were in the system. Bubbles would mean you were low on freon. You would then add freon until the bubbles went away.
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Do honeybees, wasps and hornets have a different cocktail of venom in their stings or is their chemistry pretty much all the same?
NEWQ:Do honeybees, wasps and hornets have a different cocktail of venom in their stings or is their chemistry pretty much all the same?
bitchsmackinkilla A:less answers...Bees, wasps, and hornets all evolved from a common ancestor, so their venom is similar. Basically, their venoms contain irritants that irritate the victim/the individual who was stung. Phospholipase A2 and mellitin are the allergens that cause a bee sting. Antigen 5 is the main venom of a wasp/hornet. Both a bees and a wasps venom contain hyaluronidases, but the combination of compounds really dictate how the stings work/feel. A bee will inject a venom that basically causes inflammation - similar to an allergic reaction. A Wasps’ venom breaks down cell membranes and they can sting multiple times which is why they hurt so much more: they do actual damage. Finally, bee stingers stay in the skin, and you should always remove them. Hope this helps!
drak0ni A:DISCLAIMER: While it’s not completely wrong to say they’re “similar” it’s not quite correct. The allergens found in them are well defined as completely different. Therefore just because you aren’t allergic to bees doesn’t mean not being allergic to wasps. It does not mean not being allergic to hornets. In fact they’re so variable you are unlikely to be allergic to more than one but could be allergic to any of the three.
To answer OP’s question though, they’re different cocktails. The proteins, enzymes, and pheromones are varied. Compare a bee to a cobra and yes, the bee venom will be much more similar to that of a wasp. That’s like comparing an orange to an apple though, of course the orange is more similar to a lime, but they’re all still vastly different.
Fun fact; Hornets venom actually contains dopamine and serotonin. They will not make you feel good though.
Tasnaki1990 A:Honebee venom: The main component is melittin, amounting to 52% of venom peptides. Adolapin contributes 2–5% of the peptides.
Common wasp venom: Complex venom containing amines (histamine, tyramine, serotonin, catecholamines), peptides, and proteins, including many hydrolases. The alkaline venom is quite different from bee venom, which is acidic. This varies for other wasp species ofcourse.
Hornet venom: haven't found any specific list for hornet venom but I have found that it's more similar to wasp venom. A large amount (5%) of acetylcholine makes it more painful than a wasp sting. The toxicity wildly varies from species to species. From very venomous to not very venomous (just painful).
copperpoint A:Oh man. I can’t begin to answer this but conveniently there’s an entire book on it: Sting of the Wild by Justin Schmidt (of Schmidt’s sting pain index). He addresses this exact question and lots more. Very readable.
Junebug78 A:Guy with a bee sting allergy here. Also, a former (failed) beekeeper.
I became allergic to bee venom and had a near fatal anaphylactic reaction. I now undergo shots to maintain some immunity to bee venom but I also get a hornet venom and wasp venom shot as well so there must be some difference in the three.
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Why is shorting of stocks a thing? What benefit does it provide to the market system when people can just borrow money and bet on a business to fail?
NEWQ:ELI5: Why is shorting of stocks a thing? What benefit does it provide to the market system when people can just borrow money and bet on a business to fail?
TehWildMan_ A:less answers...It's a way for large investors who are holding shares of the stock to earn a small amount of passive income, by lending the shares out and collecting interest while doing so
Lolnomoron A:To answer the why, just look at Nikola Motors.
Almost the entire company was smoke and mirrors. The investment company that released the report that proved it paid off their research by shorting the stock.
By having a mechanism to make money off downward stock prices, it financially incentivizes entities that uncover malfeasance to release that information to the public.
Just because it can be abused doesn't mean it's always a bad thing... Misuse should certainly be much more harshly regulated, but shorting isn't inherently bad.
eagle_two A:Good answers in this thread on the role of short selling and how it can benefit the market. I am going to take a slightly different angle to this: why would it not be a thing? There needs to be a reason for something to be disallowed.
A basic short sale consists of three transactions, all of which look pretty reasonable to me:
- If I want to have a share temporarily in my portfolio, and someone who has that share is willing to lend it to me for that time (for a fee we both agree on), why would we not be allowed to make that deal?
- If I have a share in my portfolio and I believe the company will go down, why would I not be allowed to sell it?
- If a share has recently dropped in value, and I now like it, or if I need to have that share to give back to a lender, why would I not be allowed to buy it?
Why would any of these transactions be disallowed? And if all three of them are allowed, that means short selling is possible.
IllBeTheHero A:It's not really borrowing money, it's more like borrowing the stock. You are essentially selling stock in the future that you haven't bought yet in the hope that, when you end up buying it, the value will be lower. Aside from the obvious personal benefit to the person doing it, when it works, there is also the general benefit of people being able to create more balanced portfolios of stocks that might go up even when the general market falls. A balanced portfolio might increase investments in it in general, and that can increase the longer term investments as well, that are not only speculative, benefitting the whole economy, at least in theory.
Bloodsquirrel A:Shorting, like speculating in general, has the valuable market function of putting pressure on stock prices to move toward their "correct" level. The process of shorting a stock involves selling it. Selling lots of shares of a stock reduces the stock price. If the people shorting the stock are correct about it being overvalued, then they will be helping it reach the lower, more correct price faster.
Also, there's no good reason for it to not be a thing. Shorting a stock won't cause a healthy business to fail, and the person who risks the most in the exchange is the person doing the short. There's no clear way in which the person shorting the stock is violating anybody else's property rights or causing undue harm to them. At worst, it'll cause an unhealthy business to lose investor confidence faster, but that's not a bad thing. And if the business is healthy, then it'll just help the people who have a better understanding of the company's value, who will be able to buy the stock more cheaply and make money when it goes up.
The GME situation demonstrates a desirable outcome: Funds that were shorting the stock lost money. They were duly punished for their poor foresight, a lot of smaller investors made a bunch of money, and Gamestop will continue to sink or swim based on whether it successfully transitions to a digital distribution platform.
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Q:
ELI5 What Exactly is Happening When Someone "Throws" Their Voice?
spleeble A:less answers...It's an illusion. They make something look like it's talking while hiding their own lip movements. They don't "throw" anything.
The "throwing" is just the brains of the people watching assuming that the thing that looks like it's talking is doing the talking.
wordboydave A:So you're suggesting, IN DIRECT OPPOSITION TO DECADES Of ESTABLISHED COMIC BOOK PRACTICE, that there's no such thing as "super-ventriloquism"? What the hell has Superman been using all these years, then?
shettrick A:Voice throwing is changing your voice in such a way as to make it sound like someone speaking from a distance. Just about anyone can change their voice to speak in a low tone or a high squeaky tone. Voice throwers do something similar and just change the tone to make it sound far off. I don’t think it has to involve echoing, since the only time I’ve heard someone do was outdoors in a completely open area.
It was pretty funny actually. This guy had my dad completely fooled as he kept making it sound like someone far off was yelling “hey Jack!” My sister and I figured it out after a couple times that he did it but my dad was clueless.
jmraef A:"Throwing" their voice is a term used to describe what a ventriloquist does. Nothing is actually "thrown", it just means that the ventriloquist is attempting to make it appear as though the sound is coming from the dummy by speaking without moving their lips. Because the dummy is sitting off to the side, the image is one of the voice being "thrown" across the gap between them.
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ELI5: Why does rubbing alcohol not damage electronics but water does?
Rangermatthias A:less answers...Rubbing alcohol (isopropyl) doesn't conduct electricity. It doesn't complete an electrical circuit and it doesn't cause iron to oxidize (rust).
Water does.
Edit: Pure water doesn't conduct electricity - as I've been informed 1000 times.
eksyte A:You can wash electronics with soap and water without damaging them, so long as there is no current running in the device. Capacitors that still have a charge can cause shorts, so this is also a potential hazard when cleaning electronics.
Alcohol is used because it evaporates faster and it's a better solvent.
bob4apples A:The most risky liquid for electronics is salt water. It causes galvanic corrosion and can act to short circuit power components.
If you ever drop unprotected battery powered electronics into salt water, you have seconds to remove the battery; you have minutes to hours to rinse out the salt water and you have days to let the clean water dry off.
You can make a galvanic cell (battery) by taking any two different metals and dipping them in an ionic solution (eg: acid, salt water etc.) When you drop your phone into salt water, the frame (aluminum or steel) and the circuit traces (copper) form a battery. The very fine copper traces oxidize (rust) rapidly. You can make this happen even faster by applying a voltage to drive the reaction.
Clean water on unpowered electronics is pretty harmless. Many electronic manufacturing processes flush or rinse with distilled water. If you leave it for a long time, the damp metal will react with air to rust and it will tend to pick up salts and contaminants that may make it act like weak salt water.
Alcohol evaporates very fast and is usually applied very sparingly. The risk with alcohol is not the electronics but the structure. Many adhesives are alcohol-soluble including hot melt (used to tack down wires and physically stressed components) tapes and, most importantly, some of the glues used to build up touchscreens. Generally the amount of mass (for glues and tapes) or the amount of exposed surface (tapes and screens) means that you need a long exposure to do much damage. Soaking a screen in alcohol overnight will almost certainly destroy it while doing the same with clean water probably wouldn't.
plageiusdarth A:Rubbing alcohol evaporates quickly. You might still have moisture from water in your electronics for days after, but rubbing alcohol is likely to be gone within minutes.
YouShouldTryHarder A:Water (H2O) has the ability to auto ionize. Meaning that molecules of water can react with one another to split themselves into two different ions. Hydroxide: [OH]- and Hydron: [H]+. Ions are very good at carrying charge, and if an electrical component is exposed to an ion containing solution it can short circuit meaning that the charge from the circuit is free to flow anywhere exposed to the solution without much resistance.
Isopropyl Alcohol (CH3)2CHOH will not ionize because molecules of rubbing alcohol will not react with one another. No auto ionization means that charge won’t run through the solution and the circuit is more or less safe
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Q:
Why do nuclear bombs form this typical mushroom cloud and not just a ball shaped cloud?
spudz76 A:less answers...Mushroom clouds form in any case where there is a very hot central feature, causing a strong updraft shaft where that heated air rises. This rising against the stagnant colder air around the circular rising center "stem" causes swirling currents in the form of a muffin top or mushroom cap.
mmomtchev A:The cloud is called a pyrocumulus and it is not specific to nuclear blasts - large forest fires and volcanos can cause it too - with a slightly different shape. It is very similar to the classical storm cloud - the cumulonimbus. Hot air rises and expands. Expansion cools it down. Eventually it reaches an equilibrium level and starts expanding horizontally until it starts falling down (oversimplification).
the_Demongod A:Another reason not yet mentioned is that the shockwave may reflect off the ground, pushing the fireball into a donut shape, which helps catalyze the other effects mentioned. Here is a slow motion video of this happening. If you think this is weird looking, I suggest reading about the rope trick effect.
BrobdingnagLilliput A:The initial cloud IS ball shaped - if you watch high-speed film of the initial milliseconds of nuclear explosions, you can see that. The ball-shaped cloud is much hotter than the air around it, and (because it's an explosion) it expands rapidly. That makes the cloud much lighter than the air around it, and it begins rising, like a hot air balloon would, but much faster, since it's much hotter and therefore much lighter.
The "stem" of the mushroom can be thought of as like a column of smoke rising from the detonation site. I say "like" smoke, because, while there's probably some smoke in that column, it's actually hot, turbulent, dusty air, heated by the energy that the ground absorbed.
Mushroom clouds are associated with detonations on or near the ground; detonations at higher altitudes generally don't have the iconic mushroom cloud.
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We're told for muscle growth you need to eat enough protein, but how important is the type of protein?
NEWQ:I'm aware of essential and non essential proteins, but pretty ignorant beyond that. For example, what proportion of your intake needs be essential protein?
dangerliar A:less answers...TL;DR: This link is a fantastic guide to protein intake for all types of diets, goals, and body types. The whole site is built around synthesizing and analyzing actual scientific studies (not just ones bought and paid for by supplement companies).
So to begin, being an ELI5 question, beware you're going to get a lot of pseudo-science/bro-science answers here. So far, what I'm seeing in this thread is mostly correct for a normal diet regime, i.e. just eating healthy. However, you mention muscle growth in your title and I see you talking about the gym in a few comments, so "just eat rice and beans" is not going to cut it for you specifically. Why? Read on.
It's very well-proven that to gain muscle with any sort of speed you need to do two things: 1) eat more calories than you burn (yes this means you will gain some fat as well), and 2) make sure these calories are comprised of a minimum of 1.5g of protein per kg of bodyweight (or 0.7g per lb). So if you're a 70kg/154lb person, you'd need to eat about 105g of protein. Adjust as necessary to your weight.
Red beans, a non-meat, relatively high-protein source, have about 24g of protein in a 100g serving (EDIT: 100g of dry beans, that is. 100g of cooked will have less). Obviously this is an extreme example and no one actually eats this way, but it's illustrative to see that you'd have to eat almost 500g of dry beans to get your daily protein. Prepare your rectum.
So what to do? You will have to add protein supplementation, but since you're vegan that means the two best "complete" proteins--whey and egg-- are out. Complete means it contains the whole range of essential amino acids, which are primarily what your body use to build muscle. Protein in and of itself doesn't build muscle - it's your body's breakdown of it into amino acids that does the work. If a particular protein doesn't have the aminos in the right amounts/ratios, it's less optimal for muscle growth.
The drawback with non-meat proteins (beans, soy, some veg, grain, etc) is that they have a much lower bio-availability of their proteins. Bio-availability is just how much of the particular element your body can actually access. With animal proteins, bio-availability is about 95%; with non-animal proteins it's about 70%. This is true for protein supplements made from plant sources as well. So either you need to eat \~25% more of it than compared to animal protein (whey, milk, meat, fish, etc), or you need to supplement the protein with EAAs (essential amino acids). These are easy to find in powder form. They are bitter so are best mixed in a berry smoothie or something like that.
All of this is to say, at the end of the day your body is an amazing machine and will more or less adapt to whatever you put in it and give you its best possible result along the way. I'm not saying that the only way you'll ever build muscle is to follow my advice. I'm just trying to lay out a simple and easy way of thinking about how to maximize your efforts.
Take everything we say with a grain of salt. I'm not omniscient and neither is anyone else (or science for that matter). Start with something reasonable, try different regimes, and see what makes you feel (and look) the best. What works for me may not work as well for you. Ultimately, if you're able to stick to regular exercise and maintaining quality food intake, that's the real victory. Good luck my friend.
OBLIGATORY "THIS BLEW UP" EDIT: Thanks to everyone for the awards and follow-up comments. Just to add two things:
- Several users have rightly pointed out that if you are overweight or new to weight training, you can gain a decent amount of muscle and be in a caloric deficit at the same time. This is true and what colloquially is called "noob gains." But as you get more trained / lose more weight, this will eventually plateau and you will need to add calories again. There is also the idea of "body recomposition" where you are simultaneously losing fat and gaining muscle. Outside of having gifted genetics, this generally takes a lot longer to build muscle than just eating a surplus. It also requires a more strict monitoring of your calories and macros. But by all means give it a shot.
- You'll notice there is an inherent bias in what I've written - it's from the perspective of someone who has trained for a long time and is of a normal weight. It's impossible to give advice to every person of every type of diet, age, weight, goal, etc in one thread. I'm simply trying to give a general overview of what I've found that works, but please don't just take my word as gospel. Find a regimen that you enjoy and can stick with and then once you do it enough you too can pass along what you've learned to strangers on the internet for super valuable internet points.
Supraspinator A:There are some great explanations in the thread, so I’m trying one for a five year old.
Proteins are like lego sets. You can build a lot of different things with the same bricks. Your body has 20 types of bricks (amino acids) with which it builds all protein the body.
When you eat protein, you disassemble (digest) one set and use the pieces to build your own sets (proteins). The more similar the 2 sets are, the easier is it to build. If you want to build a starship (your muscles), it’s best to disassemble a similar looking starship (animal muscle aka meat). If you eat castles (plant protein) you need to disassemble more castle sets to get all pieces you need for your starship.
TraitorMacbeth A:It's more about the amino acids (building blocks of proteins) than the specific proteins-
Wikipedia-
An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet.
All other amino acids, and the proteins built from them, our body can cobble together just fine on its own.
So, you generally should have these in your diet occasionally, but fortunately it's easy to do- rice & beans covers them all, for example.
petapun A:Unless you have a very restricted diet (for health or palate reasons) then you don't have to worry about it. By eating commonly available sources of protein (eggs, meat, chia, hemp etc) you will be eating complete proteins in sufficient quantities by default.
If you do have a restricted diet, i.e. a strict vegetarian and you dislike a lot of foods and you don't have time to prepare food that blend enough protein types to make your overall intake 'complete'..then you should be getting some multi-vitamins and some protein supplements to mix into smoothies.
Bottom line, if you focus on overall protein intake as a percentage of your diet calories, and eat a varied menu, then you don't have to overthink it.
Edit: added in chia and hemp as examples, as many people had mentioned them in the thread.
J-dub-suede A:- histidine cauliflower, bananas
- isoleucine spinach, blueberries, apples
- leucine kidney beans, apples, blueberries, bananas
- lysine kidney beans, black beans, tomatoes
- methionine broccoli, cauliflower, spinach, tomatoes, apples, bananas, blueberries
- phenylalanine black beans, kidney beans, bananas
- threonine spinach, kidney beans, broccoli
- tryptophan spinach, apples, oranges, bananas
- valine spinach, broccoli, apples, blueberries, oranges

So the short answer (being "how") is actually relatively simple; their tongues are so large and complex that they can use them to produce exceptionally distinct sound waves, reproducing not only human speech patterns, but the patterns of animals. Hell, any sound really, as there's been cases of domesticated parrots mimicking household appliances.
As to "why," the answer gets a bit more complicated. What's known for certain, and this is true with many species of avians, is that they have to learn or adjust to the 'local' mating call to find a mate. Imagine, if you would, you travel to a new country and now have to mimic their accent to even be seen as a viable mate, or even human. Weird, but that's how birds work particularly when their mating calls are from a distance.
Aspects of mimicry outside of mating are a bit theoretical, as it can be assumed to be bonding/play, or simple attempts at communication.
Hope that helped.
Some birds can learn to mimic the sounds of other birds and even humans. If a bird can learn to imitate a sound, they can copy the sounds others make.
Scientists wondered why some birds can learn to imitate sounds and others cannot. The new study found that parrots’ brains have special areas for learning and remembering sounds. Like parrots, birds that can learn to imitate sounds have brains with special learning areas. Birds that cannot learn to imitate sounds do not have these special learning areas. The special learning areas in the brains of birds that can learn to imitate sounds are called a core and a shell. The core is in the front of the brain. The shell is in the back.
Scientists think that this is because birds that can imitate sounds learn to copy sounds before they learn to fly. It may be that in birds that can learn to imitate sounds, the core and shell were duplicated a long time ago and have changed very little since then.
[entfernt]
They are very smart and capable animals and they are trying any way they can to survive in that prison that people put them in.
Anything to get something beneficial from their captors
A bit like a bear that's 'learning' to dance on hotplates