Wikipedia:Reference desk/Archives/Miscellaneous/2016 March 29

= March 29 =

Cheek kissing
I've read over the cheek kissing article and it only alludes to the answer to my question. When people do the double cheek kiss in greeting or such (I see it mostly with celebrities such as Heidi Klum or Gordon Ramsey), are they just touching cheeks and making a kissing sound with their mouths?

As someone who thinks hand shakes are unnecessarily ceremonious, the length of time this greeting takes bothers me to even see it. To think that the kisses are simply produced for the sound effect... It's absolutely ridiculous!

Rant aside, are they just "air kisses"? Dismas |(talk) 01:53, 29 March 2016 (UTC)


 * The Italians I met a couple months ago indicated that it is indeed just "air kissing" near the cheek in most instances instead of planting one. They did say this in response to someone who asked was overly excited at the prospect of having two strapping lads kiss her, but I recall hearing the same elsewhere.  Ian.thomson (talk) 01:58, 29 March 2016 (UTC)


 * Handshakes too time-consuming? This must be a horror movie to you. The Quixotic Potato (talk) 04:51, 29 March 2016 (UTC)


 * I think he's saying it's the "air kissing" that takes longer. And it's an old custom. I think of it as European, but in The Wizard of Oz when the Wizard awards the lion he medal, he gives him a couple of cheek kisses, though they might be actual kisses instead of air kisses. In the Tour de France, Tour of Spain, etc. the young woman presenters also go through a pair (or triple) of air kisses as part of the routine. ←Baseball Bugs What's up, Doc? carrots→ 05:31, 29 March 2016 (UTC)


 * Good point. I need to get some sleep. The Quixotic Potato (talk) 05:56, 29 March 2016 (UTC)


 * Having lived for some years in France, I think it is fair to see that the degree of physical contact involved in cheek kissing varies in line with the degree of intimacy between the people doing it. It can just be kissing the air - or it can be real lip to cheek kissing: the closer you are to someone, the more contact there is likely to be. 217.44.50.87 (talk) 08:12, 29 March 2016 (UTC)
 * Yes, this is the correct answer: it varies. I know an Italian academic. In the states, he will brush cheeks lightly with close friends of any gender, but not usually work associates. In Italy he does the cheek kiss with friends that are not as close, because they expect it and use it in their own culture. It just varies by comfort level, personal space expectations, etc. SemanticMantis (talk) 13:49, 29 March 2016 (UTC)
 * My ex- is French - and it was noticeable that there was a distinct regional difference as well as a depth-of-relationship difference and all kinds of gender differences. Some people were doing just a brief hug, others going with the single kiss (right-cheek to right-cheek), others double (right-then-left) and most of my ex's family going with quadruple (right/left/right/left).  As already suggested, there is also a spectrum from air-only, cheek-touch only, brush-with-lips-on cheek to full *smooch* on cheek, depending on degree of relationship.  You'd also get the "grab-head with both hands lips-to-cheek, wet smooch".  Since it's inconvenient/impossible for both people to manage lips-on-cheek simultaneously, there seemed to be some unwritten rule about when one person would get lip contact and the other only air.  It's definitely not a simple ritual.
 * To a rather reserved Englishman, for whom deciding whether or not to shake hands was the limit of the thing - this was all a bit overwhelming and confusing. Many times, I felt that I'd under-done it and the other person had gone over-the-top just to demonstrate how badly I'd done!  Worse still, I have Asperger's syndrome and being touched at all by people I hardly know is uncomfortable...so this was not a fun thing! SteveBaker (talk) 16:34, 29 March 2016 (UTC)
 * When I lived in France I got used to cheek-kissing, but then I returned to Canada, the English part where we don't really do that. Later I went back to France for a conference and my old office-mate attempted to cheek-kiss, but I had forgotten about it! I thought maybe she was trying to walk past me, and stepped out of the way...everyone thought that was hilarious. Adam Bishop (talk) 10:19, 30 March 2016 (UTC)
 * I find cheek kissing to be rather inconvenient. I mean who has time to drop your pants every time you greet somebody ? StuRat (talk) 12:58, 29 March 2016 (UTC)

Chelyuskin
Is there any truth to reports that the Soviet icebreaker SS Chelyuskin was escorting a second ship which was carrying political prisoners to Zekistan (more specifically to Kolyma), and when the ships got stuck in ice several of these prisoners escaped and made their way to America? 2601:646:8E01:515D:F88D:DE34:7772:8E5B (talk) 09:55, 29 March 2016 (UTC)


 * It would seem unlikely, as they would have to escape their captors, steal provisions and clothing, and find their way not only to land, but to somebody who would help them escape. They wouldn't survive for long if they just jumped ship in winter with no assistance or preparation. StuRat (talk) 13:04, 29 March 2016 (UTC)


 * The reports claim that the prisoners launched an uprising, forced the guards to flee, then repaired an emergency radio and called the Americans for help. Don't know if it's true or not -- that's why I'm asking. 2601:646:8E01:515D:F88D:DE34:7772:8E5B (talk) 23:32, 29 March 2016 (UTC)


 * Just found out -- these reports have been completely debunked: http://evreimir.com/70/ 2601:646:8E01:515D:F88D:DE34:7772:8E5B (talk) 03:21, 30 March 2016 (UTC)

fu*k *hit *unt wank c0ck d1ck....etc
Why, in the English language do most prerogatives and swear words only have four letters? Tradition, historical context? I can think of no other language with such a quirk. — Preceding unsigned comment added by 119.204.83.178 (talk) 11:42, 29 March 2016 (UTC)


 * We have an article Four-letter word, but it doesn't try to explain why. Staecker (talk) 12:01, 29 March 2016 (UTC)


 * i find it interesting however that dutch has "three-letter words", so this quirk is twice as common as previously thought  ~Helicopter  Llama~  14:08, 29 March 2016 (UTC)


 * We Dutch don't normally call them 3-letter-woorden though, but vieze woorden (dirty words). 93.95.251.162 (talk) 15:23, 30 March 2016 (UTC) Martin.


 * Also, notably, the seven dirty words, two of the seven have more than 4 letters. So it isn't always four letters.  I can come up with plenty of impolite words which have more or less than 4 letters.  -- Jayron 32 12:22, 29 March 2016 (UTC)

Not an answer to your question, but please see prerogative - it doesn't mean what you appear to think it does. Perhaps you meant expletive? --Dweller (talk) Become old fashioned! 12:23, 29 March 2016 (UTC)


 * More probably pejorative, which is something of a euphemism. --Stephan Schulz (talk) 12:43, 29 March 2016 (UTC)


 * One factor is that as English developed, the words derived from Latin, which tend to be longer, were considered to be refined and polite, while the Anglo-Saxon words were considered crude. For example, "urinate" is from Latin, while "piss" is from Anglo-Saxon. StuRat (talk) 12:51, 29 March 2016 (UTC)


 * No, "piss" is from Latin, via French. AndrewWTaylor (talk) 13:21, 29 March 2016 (UTC)


 * OK, let me revise my example then, to "turd" versus "excrement". StuRat (talk) 13:31, 29 March 2016 (UTC)


 * FWIW, consider the etymology of the word "vulgar", which just means "common", as in "the language of the people". When it was created, the Vulgate bible was written for the common people of the Western Roman Empire, and so written in their "vulgar" tongue.  The modern usage of "vulgar" as a synonym of "obscene" is VERY recent, originally, saying speech was "vulgar" just meant the speech was used by everyday people, rather than by the nobility.  In Medieval England, the common people spoke the Anglo-Saxon language while the nobility, mostly families who came over from Normandy with William the Conqueror spoke Norman French.  I'm not exactly sure why some vulgar words also became obscene words (leading to the confusion between the terms) while others did not; after all we use some words, like child (vulgar Anglo-Saxon) and infant (noble Norman French) and neither is marked as obscene.  However, the paring of shit (vulgar Anglo-Saxon) and feces (noble Norman French) does have a marked difference in obscenity.  One word is obscene and one is not.  I'd be interested in seeing why some words diverge that way, but others do not.  -- Jayron 32 16:55, 29 March 2016 (UTC)
 * The ones that became obscene all seem to be for things that are unpleasant or taboo. Its probably just that the words the nobility used when talking about unpleasant things came to be seen as formal or acceptable euphemisms, while the words the common folk used became taboo.  (Also not that many words for the common people themselves came to have negative connotations, e.g. "common", "vulgar" (already mentioned), "churl/ish", "boor/ish", "villain", "knave", etc). Iapetus (talk) 16:36, 31 March 2016 (UTC)
 * Googling for average number of letters in a word brings up sources that suggest the average for English is ~4.5, though it obviously differs on how you measure the average and what text you're using. Assuming the 4.5 value isn't completely out to lunch, it shouldn't be a surprise that most vulgar words are four letter words - many words are. Matt Deres (talk) 20:03, 30 March 2016 (UTC)

Sex with animals
Is zoophilia / besteality with animals just another normal sexual preference. Or is there something distinctly pathological and wrong about it?

I'm not advocating anything here. — Preceding unsigned comment added by 119.204.83.178 (talk) 11:43, 29 March 2016 (UTC)


 * Most understood definitions of allowable sexual activities require active consent of all parties involved. Consent requires a level of cognitive processing not normally present in most animals.  -- Jayron 32 12:28, 29 March 2016 (UTC)


 * Which if consistently applied would of course preclude breeding animals in general. I'd say if e.g. a sheep cannot 'consent' to bestiality, then it cannot consent to any sexual activity, even with its own kind. - Lindert (talk) 12:36, 29 March 2016 (UTC)


 * No, it only applies to human sexual relations. "A foolish consistency is the hobgoblin of little minds."  -- Jayron 32 12:38, 29 March 2016 (UTC)


 * I agree animals cannot and are not required to give consent, but I fail to see why this consent must suddenly be required of all parties if one of them is human. That seems a rather arbitrary rule; must sex robots also consent? (Don't get me wrong, I do not approve of bestiality, but I find this kind of moral reasoning to be unsound) - Lindert (talk) 12:46, 29 March 2016 (UTC)
 * The simple explaination is that humans are expected to follow human standards. And this is hardly unusual. For example, many countries legally restrict how animals particularly mammals can be treated by humans requiring some degree of humane treatment and limiting in some way intentional cruelty or intentional infliction of pain and distress. There's obviously no such requirement imposed on other animals doing the same to other animals. (There are those who argue only such standards should be applied to bestiality and therefore provided you don't appear to be causing pain or distress, it's acceptable but clearly many disagree.) Nil Einne (talk) 13:01, 29 March 2016 (UTC)
 * But these human standards are followed only to a limited extent when it comes to animals. Yes, we can't abuse animals, but we can kill and eat them, lock them up against their will and separate them from their families/children, use their products, make them do forced labor etc, all things we can't do to each other. My point originally was that I don't think 'consent' is a useful concept when it comes to our treatment of animals, because obviously they don't 'consent' to being killed either. - Lindert (talk) 13:15, 29 March 2016 (UTC)
 * Ok I follow your critique of the argument. But that does raise the question: if consent is not a good line of reasoning here, why do you "not approve of bestiality"? If we throw out consent reasoning, and don't allow religious moral imperatives, then I'm fairly stumped as to why I would object to my neighbor having a good time with their seemingly enthusiastic dolphin friend, whatever that might mean to the two of them. SemanticMantis (talk) 13:42, 29 March 2016 (UTC)
 * You're right: apart from finding the idea repulsive (which is subjective of course), I wouldn't be able to give a reason why bestiality is wrong if I disallowed 'religious moral imperatives', but I don't. - Lindert (talk) 14:38, 29 March 2016 (UTC)
 * You initially said "I fail to see why this consent must suddenly be required of all parties if one of them is human. That seems a rather arbitrary rule; must sex robots also consent". The point of my reply is that we apply human standards to humans. Therefore the fact that non human animals don't really consent to sex with each other is irrelevant. What is relevant is the standards we set for human which you didn't really address in your initial reply. While you're right that our standards are in some ways contradictary and sometimes arbitary, the point is that whatever standards we set for humans are derived from our on moral views on what's right for humans to do, and we don't generally pay much heed to what non human animals to do each other. In other words, if people feel that sexual intercourse involving humans always requires the consent of all parties, you're not getting anywhere by saying they're wrong because non human animals do it to each other. You need to debate it from a human POV of what we expect from humans when non human animals are involved. For example, the question of why we allow humans to kill humanely kill animals in many circumstances, but we don't allow humans to have sex with animals, even when the animals don't appear to be in pain or distress or even seem interested in being involved is a relevant one (And which I slightly hinted at in my reply), but not something which your initial reply would lead to. Nil Einne (talk) 16:41, 29 March 2016 (UTC)
 * "The point of my reply is that we apply human standards to humans." - Exactly, and when you require consent from a non-human animal, you're applying a human standard to the animal. "whatever standards we set for humans are derived from our on moral views on what's right for humans to do" - Yes, I agree completely, and my moral view is that it is simply not right for humans to have sex with animals, regardless of consent. - Lindert (talk) 16:44, 29 March 2016 (UTC)
 * "you're applying a human standard to the animal" Well firstly I never said you shouldn't apply a human standard to a non human animal. More importantly, you're not. You're requiring a human standard to a human namely that they need consent from any partners involved in sexual intercourse. The non human animal's POV is mostly irrelevant to this argument. Likewise, when we require humane treatment of animals, we're applying a human standard to humans. Most if not all non human animals have concepts of pain etc, but the concept of humane treatment is a human construct they don't understand but it's still something we apply to the humans in their interactions with non human animals. You've obviously entitled to your POV on why bestiality is wrong, and many people share it. The point is that others may say that we expect humans to only have sex with organisms when they have their consent, and most if not all non humans animals can't consent. You may disagree that's the standard that should apply, but it's ultimately a standard others do apply because they believe we should apply human standards to humans, including in their interactions with non human animals, which may include that humans always need consent from their sexual partners including any non human animals. (N.B. Some may bring up parasites etc, but while they may incidentally be involved in sex, they aren't normally the object to have sex with. Still there are complexities particularly with invertebrates or other animal forms we generally regard as simple. Yet many of these arise even for many of those who reject bestiality for reasons such as yours anyway.) Note that bringing up killing is also not necessarily helpful since we may very well have different standards for different activities. For example, most people have very strong limitations on humans killing humans even when consent is involved. P.S. I should clarify that some people may very well suggest what animals to do each other is relevant in deciding what standards we expect when humans interact with non human animals. The point isn't that this is an invalid POV since that's obviously. But rather for those who feel it's irrelevant, you're not getting anywhere by bringing it up since their POV is that's irrelevant since human morality is solely derived from what is considered acceptable conduct from humans in their interactions including with non human animals. P.P.S. There are additional complexities with dead animals and other activities like necrophilia or as you mentioned robots. Ultimately it's difficult for consent to be the only consideration but this doesn't mean it can't be a considered in bestiality. Nil Einne (talk) 17:21, 29 March 2016 (UTC)


 * The usual purposes of sex are:


 * 1) Reproduction.


 * 2) Forming social bonds. This is most obvious in the case of bonobos.


 * Beastiality certainly doesn't qualify for #1, and #2 seems to only apply if consensual. And even in the case of consensual beastiality, I'm not sure if that forms a closer social bond than would exist without it.  For example, people and their dogs already have a close bond.  So, if there is no legit purpose for it, that would seem to put it in the realm of mental disorders. StuRat (talk) 12:48, 29 March 2016 (UTC)


 * Doesn't anyone know how to spell bestiality? --   Jack of Oz   [pleasantries]  12:50, 29 March 2016 (UTC)


 * We apparently don't have as much experience with the topic as you, Jack. StuRat (talk) 12:53, 29 March 2016 (UTC)
 * That was a beastly comment. I forgive you this time, but next time I'll sool the Beastorn onto you.  :)  --   Jack of Oz   [pleasantries]  23:12, 30 March 2016 (UTC)


 * Have you read our article on zoophilia? It's pretty good, and covers many perspectives, with reference. Probably far better to read that than our replies here :) You also might enjoy reading about paraphilia in general, as well as social norm. See specifically the section on Paraphilia. That mostly discusses this in terms of the DSM, so also understand that the DSM has many critics and perceived flaws, outlined at Diagnostic_and_Statistical_Manual_of_Mental_Disorders. What is "wrong" depends on what morality, or at least what social more you consider the question within. SemanticMantis (talk) 13:42, 29 March 2016 (UTC)


 * I noticed the comment that animals cannot consent to having sex with other animals. If you think that is the case, just watch how a ewe behaves when she isn't interested in being tupped by the ram! The triggers may be hormonal, but female animals are usually well able to reject a male if the timing is wrong. 217.44.50.87 (talk) 15:51, 29 March 2016 (UTC)
 * That is true, what I should have written is that animals cannot give informed consent, i.e. the kind of consent that we require in human sexuality, where participants know what they're doing beyond purely following their instincts. Obviously animals can show when they're into an act, and this also includes cases of male animals actively participating in sex with humans. - Lindert (talk) 15:59, 29 March 2016 (UTC)
 * I think Jayron32 already expressed it well in the first reply to the OP of this whole thread of what is meant by consent. Notably if you're applying a standard of sexual consent which includes the ram-ewe case as consent, you're saying a 6 year old can consent to sex with an adult, something considered extremely repugnant in nearly all of the modern world. (This doesn't mean that it's the same thing, there are obvious differences in particular the possible long term harm. The point is simply that when we talk about consent, we mean a specific thing which isn't the same as what appears to be happening in the ram-ewe case.) Nil Einne (talk) 16:44, 29 March 2016 (UTC)


 * What about a dog jumping a person's leg? One could see it as a sign of consent so why not return the favor? :)) --TMCk (talk) 17:35, 29 March 2016 (UTC)
 * It's not consent, it's instinct. Besides which, how would you go about humping a dog's leg? ←Baseball Bugs What's up, Doc? carrots→ 21:25, 29 March 2016 (UTC)
 * All of the side discussions miss one important factor: The question is fundamentally about expectations of human behavior. Expectations appropriate human sexual behavior are predicated on the concept of consent.  Expectations of animal sexual behavior are NOT so predicated, as animals don't have the higher order thinking skills for consent to enter into their behavioral expectations.  So, when we decide "How should we judge the choice a human makes?"  that's a very different questions than "How should be judge the actions of an animal."  To keep with the last example: A dog humping a human leg is not judged the same level of inappropriate because the dog does not have an expectation to understand consent.  A human humping a dog IS judged inappropriate because the human has an expectation of metacognition, that is a human should recognize the dog is incapable of consent, and thus it is inappropriate for the human to initiate sexual contact with it.  Adult humans have a theory of mind.  Children and non-human animals do not have that at the expected, fully developed, adult level.  -- Jayron 32 12:46, 30 March 2016 (UTC)


 * Cf Bear, a novel by Marian Engel. Carbon Caryatid (talk) 22:01, 30 March 2016 (UTC)

space exploration
I was reading about how theres plan to start colony on moon, mars. Why, when will men travel to sun, and also start colony here? — Preceding unsigned comment added by 51.174.125.3 (talk) 20:26, 29 March 2016 (UTC)


 * 1) I am not aware of current plans to start colonies on the Moon or Mars, at least nothing that's been approved and scheduled. There is a long-term goal to visit the Moon again and Mars for the first time, though.


 * 2) You can't have a colony very close to the Sun, as it would overheat and mass coronal ejections would destroy it. But you can have a space station in orbit around the Sun, close enough to get all the energy they need from the Sun, but far enough away to be safe.  See Dyson ring for an eventual goal we might aim for (thousands of years from now).  StuRat (talk) 20:34, 29 March 2016 (UTC)


 * coronal mass ejections Sagittarian Milky Way (talk) 20:38, 29 March 2016 (UTC)


 * Couldn't the colonists cool the atmosphere down using colonic irrigation? --   Jack of Oz   [pleasantries]  21:35, 29 March 2016 (UTC)
 * I see the above post as trollish. Sorry Jack.--178.101.224.162 (talk) 22:06, 30 March 2016 (UTC)
 * If you're truly sorry, make an act of heartfelt contrition, resolve never to repeat your error, and go in peace to love and serve the Lord.
 * But seriously, you seem unable to distinguish between actual trollery (? trollage, trollism ...), which is designed to disrupt proceedings, do damage to the smooth running of the desks, and to be a negative influence; and occasional humour, which is designed to put a smile on people's faces, lift their spirits, improve the mood of the desks, and generally be a positive influence if not overdone. The very fact that you responded to my quip in a critical manner means that it is you who are bringing the negativity here. For that, it is I who am the sorry one now, but not for anything I have done.  --   Jack of Oz   [pleasantries]  23:06, 30 March 2016 (UTC)

Sexual attraction in gays and lesbians
Sexual attraction for straight people seems very boring, generally we're told that if your a woman you must be blond,tall skinny and if your man you must be tall, dark, rich, What about for gays or lesbians, are there any sterotypes for them, or pressure to act / behave in certain ways as per the usual hetrosexual gender roles. — Preceding unsigned comment added by 27.32.11.194 (talk) 20:32, 29 March 2016 (UTC)


 * There seem to be polar opposites of attraction in both cases. For example, some gay women are attracted to feminine women while others are attracted to ultra-masculine women.  The corresponding difference occurs in gay men. StuRat (talk) 20:41, 29 March 2016 (UTC)


 * What a stereotyped straight male allegedly prefers in a woman is irrelevant. What matters is what you prefer. I myself don't much care for skinny blondes. And a lot of other men don't either. ←Baseball Bugs What's up, Doc? carrots→ 21:21, 29 March 2016 (UTC)
 * That comment is itself irrelevant here. The OP is specifically and explicity asking about stereotypes.  --   Jack of Oz   [pleasantries]  21:32, 29 March 2016 (UTC)
 * He stated a premise. I am challenging the premise. ←Baseball Bugs What's up, Doc? carrots→ 21:35, 29 March 2016 (UTC)
 * No, he said "generally we're told .....", and acknowledged that that is a stereotype. He was not agreeing with it.  --   Jack of Oz   [pleasantries]  21:36, 29 March 2016 (UTC)
 * I challenge the notion that "we are told" such and such. ←Baseball Bugs What's up, Doc? carrots→ 21:39, 29 March 2016 (UTC)
 * How do you know what the OP and his acquaintances are being told? --Lgriot (talk) 17:52, 30 March 2016 (UTC)
 * How do you know what the OP means by "we"? ←Baseball Bugs What's up, Doc? carrots→ 17:54, 30 March 2016 (UTC)

Stop arguing and answer the question. — Preceding unsigned comment added by 92.26.107.123 (talk) 06:09, 30 March 2016 (UTC)
 * Stop giving orders. ←Baseball Bugs What's up, Doc? carrots→ 15:03, 30 March 2016 (UTC)


 * Wikipedia has articles about sexual attraction. No one here will stop you from reading that article, or any others where it leads you.  -- Jayron 32 11:42, 30 March 2016 (UTC)


 * Cf Bear, a subculture of gay men. Just as not all straight men are into slender blonde women (but many definitely are), not all gay men are into hirsute chubby blokes (but some definitely are). WHAAOE: LGBT stereotypes. Carbon Caryatid (talk) 22:06, 30 March 2016 (UTC)
 * "Sexual attraction for straight people seems very boring, generally we're told that if your a woman you must be blond,tall skinny and if your man you must be tall, dark, rich" Iapetus (talk) 16:42, 31 March 2016 (UTC)

human photosynthesis
why did humans never evolve like this, why did animal did not. We could survive without eating, no war. Like a tree? — Preceding unsigned comment added by 36.12.52.177 (talk) 20:39, 29 March 2016 (UTC)


 * I believe there are some simple one-celled animals that do engage in photosynthesis. However, the amount of energy it provides is pathetically small.  This is why plants don't have the energy to do much thinking, moving, etc. StuRat (talk) 20:43, 29 March 2016 (UTC)


 * This reminds me of a question some months ago as to why land animals don't have gills. The answer is parallel to your answer about animals not having leaves. That is, the amount of oxygen we would pull in via gills would be woefully inadequate for our needs. Fish don't need nearly as much oxygen as we do. ←Baseball Bugs What's up, Doc? carrots→ 21:24, 29 March 2016 (UTC)


 * Stu, please don't just type in your first guesses. This is all wrong. Well mostly wrong, but you didn't even link to the paramecium you were probably thinking of. All plants move, and some of them even have memory and learning capabilities. Maybe you are just trying to teach us all about Cunningham's Law, by example? SemanticMantis (talk) 21:31, 29 March 2016 (UTC)


 * Can you post some examples of intelligent plants? ←Baseball Bugs What's up, Doc? carrots→ 21:33, 29 March 2016 (UTC)
 * Sure. Note I did not say intelligent. I said learning and memory, which are more specific claims and not as strong. Here's an example of that, a Mimosa species that also happens to be one that can be easily seen to move. More generally, Plant Neurobiology is an emerging field of research - now that we know lots more about cell signalling and hormones and whatnot, we can start to see that some plants are doing things much like animals do with their brains. Here's  a whole journal that is devoted to research along these lines. There are also some critics , and we need to be careful about stretching the analogy too far. We have a somewhat relevant WP article at Plant perception_(physiology). SemanticMantis (talk) 21:44, 29 March 2016 (UTC)


 * You seem to be intentional misinterpreting my answer, so as to set up a straw man. "Movement" in this context means due to muscles, and "think" in this context means with a brain.  Yes, some plants can do rather limited movement, like a Venus flytrap, and mimic intelligence, using methods that require far less energy than animals, but that's all quite irrelevant to my point.   StuRat (talk) 21:44, 29 March 2016 (UTC)


 * Only irrelevant when you move the goal posts. Also, when you don't actually link to any reliable sources, its easy to change what you said, or claim you never meant what you said.  Instead, you could just direct people to read articles and let them think for themselves.  -- Jayron 32 01:54, 30 March 2016 (UTC)
 * He originally said "plants don't have the energy to do much thinking, moving, etc" (my emphasis).  I don't think the very limited movement that some plants are capable of contradicts that.  Also, it seems pretty obvious to me from the context that he meant "plants do not get sufficient energy to move and think the way animals can". Iapetus (talk) 16:49, 31 March 2016 (UTC)
 * Point taken. If Stu doesn't want me to read his words literally and uncharitably he should stop his habit being the first responder and including no references ;) By the way, some plants move hundreds of miles within a few days . I wasn't just being glib, most of us think about plants as sedentary, and that's a huge oversight. seed dispersal by seeds is intensely important to plant biology, perhaps even moreso than animal locomotion is to their ecology. SemanticMantis (talk) 17:06, 31 March 2016 (UTC)


 * Here is an interesting list of "higher" animals that can use photosynthesis including a sea slug, a salamander, a hornet, and an aphid! Evolution doesn't doe so well with "why" questions, but there are at least some examples of non-protozoan, non-protist real honest animals that get some energy from photosynthesis the sun (not all of the examples given are using canonical photosynthesis).  SemanticMantis (talk) 21:31, 29 March 2016 (UTC)
 * Your salamander link goes to the right picture (illustrating the general Salamander article), but a more appropriate link would be to the particular species article Spotted salamander, which includes the photosynthesis details peculiar to it. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 13:25, 30 March 2016 (UTC)


 * One thing that is important is the square-cube law – when you take a solid object and make it larger by an amount x, the volume increases by x3 while the surface area only increases by x2. In animal terms, the volume is the number of cells it contains (and therefore how much energy it needs, but see below), while the surface area is the number of cells that can support photosynthesis (since these are the ones exposed to sunlight). For a small animal that's OK - you're small, so you don't have many cells and you don't need much energy. But as you get bigger, your energy consumption increases faster than energy production (much faster – double the size of an animal, and its surface area increases x4, but its volume increases x8). The sea slug that SemanticMantis links above (Elysia chlorotica) gets around this by being incredibly flat, so it has a huge surface area (just like how trees have a huge surface area of leaves), while the salamander only uses photosynthesis at the embryo stage. Some simple maths shows why this wouldn't scale up to humans: according to this, at the equator the sunlight averages 10 kWh/m2/day, which is about 8600 calories/m2/day. Most people have a body surface area of between 1.7 m2 and 1.9 m2, so if they lie naked on their back all day long at the equator (and therefore expose about 50% of their body), about 8000 calories a day of sunlight hits them, which is three-to-four times the recommended amount of energy that the body needs. Sounds good! But (using the numbers in photosynthetic efficiency), we lose 95% of that energy straight away – either it's the wrong colour of light, or it hits the wrong part of the cell, or the sugar is immediately recycled. So really, the body can only get 400 calories maximum. The basal metabolic rate – the bare minimum a human needs to survive – varies, but it's around 1500 calories. Just to lie in the sun doing nothing would require that the body's surface area increase x4, so we'd need huge "leaves" - massive wings that we'd have to unfurl. And it gets worse if we have to move around to get water, hunt or graze (we need to get minerals and protein (or at least fixed nitrogen) from somewhere), avoid predators, take shelter from storms, reproduce, and so on. The less time we spend in the vulnerable position of photosynthesis, the bigger and flatter our bodies would have to be. Ultimately, it just makes more sense to either be huge, put down roots and never move (i.e., be a tree), or let someone else do the photosynthesising for you, and then eat them to get their sugars. If you're interested in the idea, you might want to read By Light Alone by Adam Roberts, which explores a bit what a photosynthesising human colony would look like. In the book, poor people have the artificial algae implanted in their hair, and so they grow their hair long but have to live very sedentary lives in the tropics with their hair spread around them, eating handfuls of soil and insects to get the chemicals their bodies can't produce – rich people cut their hair short and eat carbs as a form of conspicuous consumption. I found the book awfully overwritten, but the ideas are interesting. Smurrayinchester 08:41, 30 March 2016 (UTC)
 * A tiny detail I didn't mention is that Kleiber's law means that big animals are slightly more efficient than small ones in terms of metabolic rate. However, under most versions of the law this is not enough to completely counteract the effect, and if it is, it only refers to basic metabolism, not to the extra energy that animals need to move etc. Smurrayinchester 11:20, 30 March 2016 (UTC)


 * Yes, larger animals do everything slower, like slower heartbeat, slower reflexes, slower turning, and slower movement, in terms of how long it takes to move one body length. If we tried to move as quickly as a hummingbird, we would probably burst into flames from the heat all that energy usage would produce. StuRat (talk) 16:14, 31 March 2016 (UTC)


 * If I had to design a photosynthetic large animal, how about something like a manta ray, that would float on the surface to absorb sunlight on it's back during the day, while filter feeding on plankton ? It could have some passive defense system, like being highly poisonous, so it wouldn't have to waste energy fending off predators.  At night it could dive to feed from the deep.  I imagine it having a swim bladder it uses to control buoyancy. StuRat (talk) 16:20, 31 March 2016 (UTC)


 * BTW, some animals use direct energy from sunlight in another way, to increase their body temperature. Basking is quite important to cold-blooded animals, but cats like it too. StuRat (talk) 16:27, 31 March 2016 (UTC)