> 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.
How does it explain either of those things?
It 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.
Interesting 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.
I 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.
when pigeons are navigating their brainwaves oscillate around 150 - 200 Hz
a 60 fps computer display for pigeon vision is like a sequential slideshow it's much too slow to blur into what they would perceive as motion
many species of birds when they switch posture the motion is so fast it is imperceptible to the human eye it's like switching from one still frame to another
humans have perhaps 1/10th the temporal granularity that pigeons have
this leads me to the conclusion that if birds have a subjective experience it has a very different tempo than for humans or indeed most mammals
> different tempo
Cats also seem to have faster reactions that might be overlooked by our perceptive frame rate (imo, tested after recording interactions and reinterpreting them). Beyond eyesight, I suspect human breathing can be too noisy for their ears (consistent hissing).