If humans had this perception, we would sense the polarization direction in some way, perhaps something like the grain in wood.  We can use a polarizing filter to get much the same information a bee gets. (Some sunglasses are polarizing filters.)  Rotate the filter: the direction of polarization is shown by the position of the filter that gives the maximum darkening.

Humans do have just a trace of polarization detection.  It appears as "Haidinger's brushes," a very faint bluish and yellowish pattern that looks something like a cross or "x," somewhat smaller than a full moon.  You can see them by staring at a brightly lit uniform white surface while holding a polarizing filter in front of your eyes.  Rotating the filter will help you see them because the pattern rotates with the filter.  RTN
 
 
 
 
 
 
 

Sharks can use the weak electric fields that many animal organs generate to get information about potential prey.  What the shark learns is pretty much a mystery to humans.

Electric field potentially has many kinds of information.  For each each and every point in space the field has a magnitude and a direction, and both will, in general, vary with time.  This potentially carries a lot of information.  Humans use sensitive instruments to get useful information from electric fields: for example; the electrocardiogram and electroencephalogram shows the time variations of  fields within the body; and they are shown in several directions (several directions because several leads are attached).  RTN
 
 
 
 
 
 
 
 

Bacteria and some birds use perception of the Earth's weak magnetic field for navigation.  Some creatures have a built-in magnetic compass.

Magnetic field potentially has many kinds of information.  For each each and every point in space the field has a magnitude and a direction, and both will, in general, vary with time.  This potentially carries a lot of information.  Humans use sensitive instruments to get useful information from magnetic fields:  for example; magnetic orientation of minerals that have solidified as they join the spreading of the ocean floors have shown us much about the movements of continents.

The similarity of electric and magnetic fields is much more than coincidence.  They are, in fact, two aspects of the same thing. That "thing" is the interaction between the charged particles—the electrons, protons, etc,—which constitute much of what we are made of.  When the "interaction" spreads as a wave, that combination of electric and magnetic field is light.  (At least that part of it which we can see, we call "light."  The part we can't see took humans a very long time to discover.)    RTN
 
 
 
 
 
 

Insects see ultraviolet.  They can see certain patterns in insect wings and in flower petals that we are blind to.  They can see the ultraviolet which gives us sunburn.

Although "ultraviolet" is defined as light which has a wavelength outside the range of human vision (on the shorter side), the cutoff is not sharp, and our night vision is more sensitive to uv than our day vision.  Our retinal rods—which become denser farther from the center—have substantial sensitivity to the nearest uv, compared with the cones.  Get dark adapted, and look through a spectroscope, and you will see, especially in your peripheral vision, shades of violet which you can see in no other way.

Humans have another "perception" of ultraviolet, too: sunburn!  But the sensation is so far removed from the reception of the radiation that evolution didn't bother to give us clear interpretation.  We have to use a lot of our wits to really get it right.  (See "Obvious Yet Unobserved Things in the Sky."  Here.Use your "Back" button to return to this page.)   RTN
 
 
 
 
 
 
 
 

Insect vision is omatidia perception, which does not form images, as is done in our eyes where they are detected by a retina.  So we really don't know much about what kinds of image information an insect gets from vision.  Most people know that a bee or fly eye looks a lot like a bee's honneycomb.  So a lot of people imagine that such an eye produces a honeycomb-like array of images.  (See it: and use your browser's "Back" button to return to here.)  But that's profoundly wrong.

Insects are so small that images could not be formed by a lens-focused image-retina system.  The shortest wavelengths of light which are not absorbed by the atmoshpere are about as large as, or larger than, the eye parts of insects.  When the images are as small as insect eyes, they are destroyed by diffraction.   RTN

Bats and cetaceans perceive images with sound.  Bats fly in the dark of caves.  Cetaceans manuver in the dark of the deep ocean.  Knowledge of positions and shapes give the possesor of such perception a great advantage.  That's pretty obvious to us, when we realize the importance of our vision.  But we have no hint as to just what a bat or cetacean "sees" with sound.  There's no reason to think their "sound vision" resembles the images from the human invention, sonar.

Richard Feynman once put the problem of seeing images from sound in a revealing perspective.  He suggested we consider the waves and ripples on a swimming pool full of active children.  We should consider the mathematical analysis we would need in order to analyze all that wave activity and deduce the sizes, shapes and motions of the objects producing the waves.  It's a very formidable task.  Yet, that is very similar to the prosaic task our eyes, as a living-organism, analogue computer, must accomplish to give us the information vision gives us.  Evolution is capable of wondrous feats.  Our imaging with light evolved because, in part, we are immersed in light most of the time, and the imaging is possible.  So evolution found a way to do it.  Bats and cetaceans live without light much of the time but still need that image information.  So evolution found ways to give it to them.  We have a lot of difficulty imagining how sound imaging might get done, simply because that isn't our way of imaging.  RTN
 
 
 
 
 
 
 

Birds see "higher dimension" color than do humans.  Human color is three-dimensional.  Bird color is four, five, or six dimensional.  Full color is potentially infinite dimensional: this is the wavelength discrimination a spectroscope gives us.  That "infinity-space" color is one of the things it took humans a long time to discover, and it remains today one of the more difficult concepts for us to understand.

We are, in fact, visually blind to the color a bird sees and somewhat "logic blind" to the knowledge it gets with its color vision.  Click on the chick to dig deeper into this profound puzzle.   RTN