One kind of light that is mostly invisible to the human eye is polarized light, which comes from sunlight reflecting off brilliant surfaces. Polarized light spoils our clarity of vision on sunny days. It appears as flashes on the sea or an asphalt road. In order shield our eyes from this light, we use sunglasses. We need to do this even though the naked human eye only perceives a very small amount of the polarized light on earth. However, this is not a shortcoming. On the contrary, it’s a blessing to us. If we were better able to perceive polarized light, we would not see any object clearly, owing to the dazzling lights around us.

As evidenced by polarized light, the human eye is actually quite limited. Just as it cannot see radio or television waves, it cannot see ultra-violet light either. Since ultraviolet light is harmful to the retina of a human eye, it is prevented from reaching the retina by the eye’s external structures.

Every animal has a different ability and threshold when it comes to seeing colors. For example, honeybees have three-color vision, just like humans do. In the human eye, there are three types of conical cells that perceive wavelengths in red, green, and blue. All other colors are perceived as mixtures of these three colors, albeit in different proportions.

Just as there are colors like green or red, ultraviolet light has a color of its own. We do not name the color, for we cannot see it, but ultraviolet color exists for many other creatures. Since it is a very dense and brilliant form of purple, other colors would be more distinct and difficult to perceive if humans could see ultraviolet.

Bees have very complex eye structures including comb-shaped units made of cells that perceive ultraviolet color. These cells are necessary for bees to be able to see ultraviolet light, because they locate their own position and the direction they will fly according to the existing position of the sun. They use ultraviolet light to find their hives or flowers with nectar. In experiments, researchers observed that when another source of light was used instead of sunlight, bees were unable to find the direction of their hive. Even on a cloudy day, it is easy to perceive ultraviolet light. Thus, bees can locate the position of the sun and then find the direction and place of flowers containing honey. Surely, the colors and patterns of flowers appear differently to bees than they do to humans.

Honeybees also see polarized light. They use it to determine the exact location of the sun at any given moment. However, as polarized light might dazzle the eyes and reduce clarity of vision, the eye cells of honey bees are placed at the back and upper part of the eye’s structures. Since a honey bee does not see polarized light with the lower part of its eye, it is not dazzled by such flashes and reflections. It uses the upper and back portions of the eye to see polarized light, and can thus to determine which direction to fly. This trait is not unique to bees; for instance, hummingbirds, which feed on flower nectar, also perceive ultraviolet light.

Bees’ eyes are surrounded by a dense layer of tiny hairs, which help them to navigate in windy weather. These tiny hairs have nerve extensions within them. They sense the slightest hint of wind, sending the relevant information to their brain and pointing them in the right direction.

As mentioned above, a honeybee’s eye is a very complex structure. It is a unified form of more than 8,000 hexagonal and simple eye units. Each of these simpler units has its own lens, crystal, and sight cells. This united (or combed) eye system enables a honeybee to perfectly perceive the slightest movement that occurs around it. While the human eye can only see movement across 180 degrees, a bee’s eye will recognize the slightest movement across 360 degrees. Thus, it can notice every kind of possible danger and take protective action.

A honeybee sees moving objects better than unmoving ones. Therefore, honeybees are more likely to visit flowers shaking in the wind. For this same reason they are more likely to attack people running away or moving their arms or legs. Honeybees see moving objects better than stationary ones because their vision is very blurry, at least relative to human eyesight. They see objects with 1/60th the clarity of human vision. In other words, an object we comfortably recognize from a twenty-meter distance, a bee must be as close as 30 cm to recognize. Thus, honeybees see the whole world virtually like a honeycomb. For example, they see a human face in a fragmented and blurred way, as if looking at it from behind a milk-glass.

Bees are supposed to harvest honey from flowers, and the sight system they possess is exactly as needed for this purpose. Conversely, the human eye consists of a single cornea and lens system. For this reason, humans see an unmoving spot much more clearly and smoothly. While we cannot detect flower nectar from afar, humans are endowed with the ability to behold and appreciate the beauty of a flower. And this is what we are meant to do.

When a honeybee discovers a new source of honey within about ten metres of the hive, she returns to the hive and regurgitates drops of honey which are eagerly drunk by other bees. Then, in order to indicate the source of the drops they have just drunk, she performs an interesting sequence of movements we call the ‘round dance’. She dances round in a circle, first in one direction, then reversing and going round in the opposite direction, again reversing and so on. During the performance, other bees follow her about, holding their antenna against her abdomen. After the dance, she flies back to the food source, normally a particular flower or group of flowers. The other bees who followed the dance do not fly after her but fly out in all directions. However, fairly soon, a great number of them find the new source. They do so because they have smelt the scent of the flowers that clung to the dancer’s body and so to recognize the right kind of flower. Observing this procedure of the bees’ communication with admiration, Frisch reported that the ‘round dance’ tells the other bees to go out and search in the near neighbourhood of the hive; and the scent on the dancer’s body tells them which flowers to look for. In one experiment, bees informed by a dancer at once found the right flowers in a section of Munich Botanical Gardens where 700 different plant species were blooming.

But honeybees search for food at a greater distance than 10 metres. They have been observed to fly more than 13 km in search of honey. Remembering the average that a honeybee is only about 13 mm long, that 13 km for a bee is the equivalent of about 1,600 km for a human being. It is clear that, even for distances considerably less than 13 km, the round dance would not be much use. If the discoverer of a new food source informed the other bees to go out and search in all directions for over several kilometres, they would never find the flowers. Thus, when a bee finds food at a considerable distance, say over 100 metres from the hive, she returns to the hive, offers the honey she has found, and then performs a different kind of special dance. She dances along in a straight line for a certain distance, wagging her tail vigorously and buzzing away by means of slight vibrations of the muscles that flap her wings in flight. At the end of this wagging run, she stops buzzing and wagging her tail, circles round to one side back to where she started, does another wagging run, circles round to the opposite side, does a third wagging run and so on. This sequence of movements is called ‘tail-wagging dance’. Showing special interest in wagging runs, a number of other bees follow her round. It is known that bees cannot hear sounds in the air, however they can feel the buzzing vibrations through the surface on which the dance is performed. Like the round dance the ‘tail-wagging’ dance tells the followers of the dance that there is food available, and what flowers to look for, from the smell. But it tells them much more than this; it tells them precisely how far away the flowers are, and in exactly what direction. And so, the bees who study the dance can fly with precision to the spot indicated, even at a distance of kilometers, and find the honey-bearing flowers.

The distance to the food is conveyed by the tempo of the dance. A quick-step tempo means a relatively nearby food source, a slow tempo means a more distant one. More precisely as the distance increases, so does the duration of each wagging run. The bees who follow the dance study several wagging runs and then appear to calculate the average duration which they then translate into distance by a mathematical rule.

The ‘tail-wagging dance’ is sometimes done on a horizontal surface just outside the hive. When this happens, the dancer indicates the direction of food by aiming her run in exactly the direction of the food. She can do this if she can see the sun (or the polarized light of the blue sky, which indicates the position of the sun to bees, though not to us). So, actually she is taking up a position in which she sees the sun as the same angle as during her flight to the honey source. The wagging run makes the same angle with the sun on her outward flight did. But the dance is normally performed in the dark inside the hive, on the vertical surface of the honeycomb. Here the angle between the flight path and the sun is translated into the angle between the wagging run and the vertical direction straight upwards.

Another remarkable fact about the bees communication is that if the bee reached her goal (and returned from it) by an L-shaped detour, she uses the angles and lengths of the two sections of flight to calculate the true direction of the goal by straight-line flight, and this is the direction she conveys in her dance, even when she did not this direct route herself.

As for the bees who are following the dance, they are working literally in the dark and can only use touch to find out the angle of the dancer’s wagging run against the vertical. They translate this back into a visual angle with the sun, fly off in this direction for the distance signaled by the wagging run tempo, and look for the flowers of the scent they smelt on the dancer.

So far we have described the language of the Carniolan race of honeybees according to the findings of Frisch. Other races have different ‘dialects’. German, North African, Caucasian, Italian honeybees all indicate distance and direction by much shorter dances than the Carniolans. How the honeybees have learned to communicate with each other is certainly remarkable! However, it is not a true language, because the system used by bees, unlike human languages, cannot generate new combination of structures and symbols to describe novel events. One example of their limitation is that bees appear to have no way of communicating height or depth beyond a few meters. Thus, if you take a bee to a source of food in a place, say 10 metres above ground level, she will return to her hive and try to indicate the food source by means of her dance. Then, the other bees will all fly out in the direction she indicated, but they will never find the source. No matter how near the source is, even if it is just above the hive, the result will be the same.