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The bird eye was pushed to an evolutionary extreme
- deleted 5mo ago[deleted]
- ordu 5mo ago> The retina is one of the body’s most energetically expensive tissues. I never knew, but it explains why when you close to fainting you lose your vision. Or when you are working at high heart rate close to your maximum. It works as a kind of a warning sign, than you are probably shouldn't try it that hard. > The lack of blood vessels could also offer birds the advantage of better vision. Now they are ready to reintroduce blood vessels back, but this time behind the retina.
- yieldcrv 5mo agoHow does it explain either of those things?
- ordu 5mo agoWhen you have not enough oxygen it breaks. And parts using a lot of it fail first. Vision fails first, not memory, or thinking. Thinking is impaired but still works. I'm not sure how fainting works, but fainting looks to me like an energy crisis, so kinda not surprising the results are the same.
- KineticLensman 5mo ago> Vision fails first, not memory, or thinking I've had two complete blackouts due to Ventricular Fibrillation, and one near blackout where the VF stopped after nine seconds (as reported by my ICD). In my experience, vision and thinking seem to stop at the same time, with increased dizziness being the first functional effect (after perhaps 7-8 seconds). My ICD is set to fire at 14 seconds, by which time I'm guaranteed unconscious and won't feel the painful shock. It takes 2-3 seconds to recognise the warning signs (painless fluttering sensation in my chest), so there are 4-5 seconds of normal consciousness when I can try to make sure I fail safe. Like sitting down. This is why I don't drive anymore.
- Sharlin 5mo agoYou can get "tunnel vision" and blurred, black-and-white vision from anything that even slightly hinders blood flow into the head, including everyday things like going from lying down to standing up too fast, or stretching positions that make your neck muscles press on the carotid arteries. Never mind things like fighter pilots doing high-gee maneuvers.
- ordu 5mo agoHmm... Maybe the dynamics is different? When you push yourself physically your body don't stop getting oxygen suddenly, just the rate of oxygen absorption is less then you are consuming, and it is getting worse, when excesses of lactic acid reach your liver and it starts to suck out oxygen from blood to metabolize it. But the heart pumps blood at its maximum, some limited amount of oxygen is available. I'm not sure how VF works, but maybe the deficit of oxygen develops much faster, so it leads to complete blackout in seconds? > there are 4-5 seconds of normal consciousness when I can try to make sure I fail safe. Like sitting down. Fainting and workout take more time. Definitely more. When I fainted it took tens few minutes from the moment I broke my leg. When I ride my bike up to a hill with all my might, it takes a couple of minutes to see darkness in my eyes.
- WalterBright 5mo ago> Or when you are working at high heart rate close to your maximum. When I was in college, running on the track, I decided to see how fast I could run by ignoring the stress and pain. My vision began rolling and surging in a weird way impossible to describe. I stopped and laid down on the ground, unable to do anything but pant. I realized that what I had done was extremely stupid and never did it again.
- kreelman 5mo agoInteresting title. These thoughts are before reading the article, use grains of salt as required. I believe that birds brains are kind of uniquely advanced too. Lightweight (in terms of mass) structured differently to mammalian brains... I've heard a definition of sight as "a bit of the brain popping out for a look". I wonder if the same brain density tricks bird brains use are used in some parts of their vision system. This is all as my memory serves. Feel free to correct any mistakes in my understanding. There's some very interesting work happening to understand their calls too. If (my) memory serves, there able to identify particular call types quite well now. If someone calls you a "bird brain", perhaps that could be taken as a complement! Trying to do more with less! Fascinating to also think that birds are of course evolved dinosaurs. Raptors of the sky. It would be fascinating to link whats being looked at here with any kind of data that can be pulled from fossil evidence (though there might not be much...). I wonder which unique bird genetic traits were useful or super enhanced dinosaur traits. ...I think the strong but light bone structure was something inherited from the dinosaurs too? Fascinating creatures. On the face of it, seems sensible that avian evolution has spent many genetic GPU cycles to generate advanced vision needed to fly and hunt from the air.... One wonders which "subroutines" have been reused from dino-days, as mentioned.
- nkoren 5mo agoI had an an interesting experience with a bird brain today. There's a robin who often sits in the fig tree in my back yard, giving friendly little chirps whenever I'm near. (I have no way of knowing whether it's the same robin from day to day, but if it's different robins then they all seem to be on the same wavelength.) Anyhow, today a neighborhood cat came to the back door, and was aggressively friendly when I opened it. Clearly offering affection in exchange for... what? I've never given this cat anything before, apart from a friendly pat. Meanwhile the robin was overhead in the fig tree, giving totally different chirps than I'm used to. Clearly "warning!" "danger!" chirps. It was amazing how unambiguous they were. I was puzzled who the robin's audience for this was, however. I'd never noticed it freaking out about cats before. Was it trying to warn me for some reason? Trying to warn other nearby birds? I couldn't see any. I thought that maybe it was just shouting at the cat out of general pique. Then the cat led me to the answer. Turns out it had trapped an (uninjured) baby squirrel behind a planter box near my door. It couldn't reach the squirrel, and the squirrel couldn't escape. The cat seemed to be under the impression that since we were now friends, I could move the planter box and help it to get the baby squirrel. Sadly I had to disappoint it, and after unexpectedly acrobatic shenanigans, I facilitated the squirrel's escape instead. The robin, meanwhile, ceased its warning chirps the moment it saw that I was aware of the baby squirrel. Then it watched the ensuing affair unfold, from the safety of the fig tree. Once the squirrel was safe and the cat had left disappointed, the robin looked at me, gave a few of its usual happy chirps, and flew away.
- ETH_start 5mo agoIt is plausible that the original non-avian theropod dinosaurs which gave rise to avian theropod dinosaurs like modern birds were more vision-oriented predators than mammalian predators. That would have favored eyes built for sharper vision at the expense of higher metabolic demands. The different evolutionary track may come from the fact that theropods stood upright on two legs, so they could scan farther across the landscape. Also, they were active during the day. Early mammals, by contrast, were mostly nocturnal, so hearing and smell mattered more than sharp vision. Interestingly, humans have some of the best vision in the animal kingdom and humans are both upright standing and diurnal, i.e. active in the daytime.
- awesome_dude 5mo agoIt really hit me moving to Australia, most of the mammals are nocturnal (Kangaroos were the ones that caught me most by surprise) - most (if not all) of the reptiles are diurnal - got to have that sweet sweet sun to warm the blood.
- inglor_cz 5mo agoMany mammals have become nocturnal in order to avoid humans. In Central Europe, most of the big game (boars, deer etc.), but also foxes and hares have become nocturnal. The great exception is the Exclusion Zone around Chernobyl, where they all have reverted to diurnal life and tourists will quite often encounter something like a fox walking right in the middle of a road, looking at them with curiosity. Everywhere else, that would be sign of rabies, but there, it is the original normal behavior.
- dhosek 5mo agoWhich means the Jurassic Park tyrannosaur that could only see things that moved was probably seriously inaccurate (also in reality it probably had feathers).¹ ⸻ 1. While checking Wikipedia to confirm my belief about feathers, I found that the consensus among paleontologists was that tyrannosaurs had superb vision, better than humans, in fact.
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- julienchastang 5mo agoThe photography of the bird eyes in the article is stunning especially the 3x3 grid.
- hombre_fatal 5mo agoYeah, they help remind me that eyes are strange biological sensors rather than the cartoonish familiar things I see daily. Kind of like when you take acid and realize how weird you look. Or your cat’s basically a mouth with legs.
- Razengan 5mo agoWait till you see cephalopod eyes!
- SoftTalker 5mo agoIIRC cephalopods branched off very early in the evolutionary chain. They are almost like aliens.
- HexPhantom 5mo agoOnce you look closely, theiliar animal face kind of disappears and you're just staring at alien biological hardware
- qsera 5mo ago> eyes are strange biological sensors I was always amazed at the idea of a Radar, how it can detect objects at large distances by using reflected EM radiation, then I remember that eyes are just a RADAR and I am 10x amazed by the fact....
- drcongo 5mo agoSomeone on the Infinite Monkey Cage (I think) described almost all animals as just a tube - stuff goes in one end, different stuff comes out the other end.
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- VeninVidiaVicii 5mo ago> Could this be an adaptation, or is it a coincidence of evolutionary history? Ha! It’s the same thing.
- HexPhantom 5mo agoEither way, the bird ends up with the same strange bargain: unobstructed vision paid for by an inefficient metabolic workaround
- jibal 5mo agoEvolutionary biologists disagree. Adaptations are the result of numerous evolutionary coincidences, but not all evolutionary coincidences are adaptive. Not only are most survivable mutations neutral, but there are traits that are truly "coincidental" in that they come along for the ride, like the color of our blood being red being due to chemistry, not adaptation. (Our visual system that treats red as an alarm, OTOH, is adaptive.) See also https://en.wikipedia.org/wiki/Genetic_drift https://en.wikipedia.org/wiki/Genetic_drift
- gobdovan 5mo agoTechnically, every adaptation is evolutionary history, but not every evolutionary historical pattern is an adaptation. The distinction is very sharp and clear: adaptation is not a mere property discovered in the organism, but an exciting post-hoc human classification of evolutionary history. It's powered by the grand human psyche doing what it does best: projecting competitive, status-oriented social psychology onto non-human biological processes. If you ever wondered "how dare biology fail to conform to a clear narrative easily processed by the human mind?", adaptation fixes exactly that.
- hanwenn 5mo agointeresting article, but now I'm left wondering how the glucose gets to the retina. Why is this easier than supplying oxygen?
- Aerroon 5mo agoMy understanding is that glucose diffuses from the pecten oculi into the vitreous humor (it's the jelly-like thing that makes up most of the eyeball) and from there glucose diffuses into the inner retina. I'm not sure why this is easier, but I'm guessing it has to do with how much oxygen you need for aerobic glycolysis. In blood, glucose just exists in the plasma by itself, oxygen has to be carried by red blood cells. Without blood vessels it's probably difficult to get enough oxygen through diffusion into the inner retina. Fun fact: the human cornea also doesn't have blood vessels. Instead oxygen diffuses from the atmosphere into it and from the aqueous humor - a fluid? behind the cornea. The aqueous humor is also where the cornea (and the lens) get nutrients from. Yep, your cornea basically breathes!
- jibal 5mo agoWho said anything about being easier? This way of providing energy evolved because of evolutionary pressure to see better.
- dnnddidiej 5mo agoWould be great for modern humans as plenty of calories available for an inefficient but better vision eye.
- jdthedisciple 5mo agoGreat article but I don't get their insistent on "inefficiency": They start out saying oxygen vessels partially and subtly occludes vision. So the bird's eye doesn't suffer from this disadvantage. In other words: It uses 15x more energy but presumably also sees 15x sharper and more into the distance than our human eye. Sounds proportional at most, but certainly not inefficient for the bird's purposes?
- jibal 5mo agoEvery mention of efficiency is about the chemical process, not about vision as such. > anaerobic glycolysis that is significantly less efficient than oxygen-powered metabolism > Oxygen molecules make energy production in cells extremely efficient. > the presence of oxygen makes energy extraction from a single glucose molecule 15 times as efficient, and sometimes more. > This energetic ability is powered by an inefficient metabolism. > This suggested that the strange structure wasn’t bringing oxygen into the bird’s retina; rather, it was helping to pump glucose in, thereby enabling the less efficient anaerobic process.
- jdthedisciple 5mo agoYou cannot ignore the tradeoffs and the output produced: > Though we normally can’t perceive them, these vessels always occlude a portion of what we see, and for an important reason. Efficiency is input / output, not just input. 15x input / 15x output is just as efficient as 1x input / 1x output.
- jibal 5mo agoYou complained about the article's talk about "inefficiency" -- you quoted it. But as I noted, THEIR mention of efficiency/inefficiency was ALWAYS about the chemical process, not about efficiency of vision. Now you're totally moving the goalposts. I don't understand why you're playing such an obviously absurd game but I will leave you to it.
- jdthedisciple 5mo ago
- sorokod 5mo ago>the avian lineage had split from crocodiles Aren't crocodiles and dinosaurs seperarte branches ?
- Aerolfos 5mo agoThey have common ancestors, but it really should be "the crocodiles had split from the avian lineage", with avians including dinosaurs at that moment in time
- jibal 5mo agoA split is a split. Archosaurs split into a crocodile line and a dinosaur/bird line--"the avian lineage" (birds being a kind of dinosaur, and the only ones still living) ... that's what "the avian lineage had split from crocodiles" means -- it is not saying that birds are an offshoot from crocodiles, it's saying that the two lines (both kinds of archosaur) split from each other. Likewise, crocodiles are not an offshoot of dinosaurs.
- brabel 5mo agoThe funny thing is that it would make more sense (going by our popular impression of what dinosaurs looked like) if dinosaurs were in the same lineage as crocodiles, not birds.
- jibal 5mo agoNote the word "lineage". That would include the dinosaurs that were ancestors of birds. Birds are dinosaurs, so reword the statement as > the dinosaurs had split from crocodiles Birds and crocodiles are both archosaurs (which includes all dinosaurs as well as crocodiles) and are each others' closest living relatives.
- zapkyeskrill 5mo agoGuess they don't need to wear baseball caps or sunglasses when flying looking directly at the sun
- HexPhantom 5mo agoApparently they skipped sunglasses and evolved a glucose-hungry retina instead. Seems like an expensive solution, but hard to argue with the results
- pishpash 5mo ago[flagged]
- Terr_ 5mo ago> (tumor cells often use anaerobic glycolysis to make energy) More generally, human cancers cells often seem like they've rolled-back to an earlier, atavistic set of behaviors. I wonder if that's a "direction" of random mutations which is less-likely to be attacked by the immune system, because it leads to things that are less-alien because they were normal at one point. (Or may still be normal in limited contexts.) Ex: > The hallmarks of cancer are not the acquisition of novel behaviors due to genomic mutation but rather the re-deployment of ancient, unicellular programs that support survival of the cell at the expense of the host and break the contract of cooperation required for multicellular life. https://www.sciencedirect.com/science/article/abs/pii/S007961072100095X https://www.sciencedirect.com/science/article/abs/pii/S00796...
- 0cf8612b2e1e 5mo agoI assumed this was more that the robust system survives. Oxidative phosphorylation is complicated, requiring many participating proteins in the pathway. If any of them are broken, that is it. Glycolysis is comparatively simple more likely to survive random mutation. Any cells which break glycolysis will die off.
- rolph 5mo agoOxygen-Starved Tumor Cells Have Survival Advantage That Promotes Cancer Spread[2019] https://www.hopkinsmedicine.org/news/newsroom/news-releases/2019/11/oxygen-starved-tumor-cells-have-survival-advantage-that-promotes-cancer-spread https://www.hopkinsmedicine.org/news/newsroom/news-releases/...
- WalterBright 5mo agoCheck out the book "The Red Queen". The author points out that even chromosomes fight for survival at the expense of other chromosomes and the body. X chromosomes try to destroy the Y chromosome, for example. https://www.amazon.com/Red-Queen-Evolution-Human-Nature/dp/0060556579/ https://www.amazon.com/Red-Queen-Evolution-Human-Nature/dp/0... This is one of the most fascinating books I've ever read.
- tyre 5mo ago
- HexPhantom 5mo agoSoo evolution doesn't always optimize for biochemical efficiency in isolation. Sometimes it optimizes the whole system, and "wasteful" metabolism can be the right answer if it removes a bigger constraint.
- ivanbakel 5mo agoNatural selection can only work at the granularity of whole organisms, since they're the things that compete and reproduce. There is no finer pressure on specific concepts like efficiency, except that they may help the organism survive - but whatever solution works for the whole organism, works.
- dredmorbius 5mo agoMore accurately: of populations of organisms, so long as there's direct genetic transmission throughout that population (e.g., sexual reproduction or possibly if sufficiently prevalent forms of horizontal gene transfer). Heritable differentiation which benefits the population as a whole will tend to be selected for, so long as those aren't overtly nonbeneficial to individuals, and may well explain various non-overtly beneficial adaptations.
- Sharlin 5mo ago> always Ever > sometimes Always
- KineticLensman 5mo agoBirds have all sorts of optimizations that improve efficiency, some of which make them very different from mammals. Their lungs are different from ours in two respects. Firstly, they are relatively rigid and the pumping is done primarily by separate air sacs. Secondly, they have an outlet pipe so can take in new air while also expelling the old. The result is continuous oxygen exchange rather than a breathing-in/breathing-out cycle like mammals. You can see the effect in how prey is eaten after a hunt. A mammalian sprint-predator like a cheetah has to catch its breath before eating what it has just caught. Its avian equivalent, like a Peregrine falcon, can immediately start eating.
- ainch 5mo agoI've only discovered Quanta this year but it's quickly become my favourite publication. The focus on quality articles across science, and especially pure maths, feels very unique. I don't know whether it's profitable or reliant on the Simons Foundation funding - but hopefully it's a sustainable business model that will stick around.
- mmooss 5mo agoThe paper on which the article is based: https://www.nature.com/articles/s41586-025-09978-w https://www.nature.com/articles/s41586-025-09978-w Damsgaard, C., Skøtt, M.V., Williams, C.J.A. et al. Oxygen-free metabolism in the bird inner retina supported by the pecten. Nature 650, 657–663 (2026).
- deepsun 5mo agoYet birds eyes still have nerves on top of light sensitive cells, obstructing the light. Birds also have a blind spot on each eye where nerves need to pierce the retina to go to brain. Contrast with squid eyes, that have nerves underneath the light sensitive cells. No blind spots, better light sensitivity.
- 486sx33 5mo ago[dead]
- phansel 5mo agoI don't know, man, that bottom left image sure doesn't look like a bald eagle.
- hanjeanwat 5mo agoit's a juvenile, which has a brown head!