Running around looking for food, the mouse feels safe under the umbrella of darkness. And he isn’t aware that the snake “sees” the heat his body expands, which in his case is a fatal failure. One dab resting completely hidden under the sand in the pool where the hungry shark circulates, approaching closer and closer. Although he can not see the fish, a shark dog stops at the moment, sticks his nose into the sand and gathers his prey.
Yes, the snake and the sea shark are only two of many animals endowed with special senses that people do not possess. On the other hand, many creatures have the same senses as humans, they are much more mature or respond to a slightly different range of stimulant. One good example is the eyes.
Eyes that see a different world
The colors that the human eye perceives are only a tiny part of the electromagnetic spectrum. For example, our eyes do not notice infrared radiation, whose waves are more extended than red light waves. However, snakes have two small organs between the eyes and the nose, the so-called junks that are used to detect infrared radiation. Because of this, they can catch their prey in complete dark with extreme precision.
At the very end of the purple part of the visible spectrum begins the area of ultraviolet (UV) light. Though it is invisible to the human eye, numerous creatures, including birds and insects can see it. For example, bees, thanks to that light, may orient themselves toward the Sun even when it is curled by the clouds by observing the image of a blue sky which is made by the polarized ultraviolet light.
Many plants with flowers have patterns that are visible only within the ultraviolet spectrum, while some petal flowers even have special nectar tags, sections which reflect the ultraviolet light and so point insects to the nectar. Certain fruits and seeds in a similar way turn the attention of birds to themselves.
Since birds can also see the light of wavelengths within the ultraviolet region and that light gives their feathers a special glow, they are more vivid to each other than to humans. Birds enjoy “the depth and richness of colors that we can not imagine”.
Certain types of hawks have the ability to spot ultraviolet light and it can even help them to find out where there are common voles. How? The voluptuous males, “eject urine and feces that contain chemical substances that absorb ultraviolet rays and thus leave traces of it.” Thanks to this, birds can “spot areas where there are lots of voles” and concentrate on them.
Why do birds see so well?
The bird’s eye is indeed a miracle. “Most of this” can be attributed to the fact that the tissue in which the inside of the eye is created and in which the image is created, has far more sight cells than the eyes of other creatures. Namely, on the number of visual cells depends on how well will the bird observe tiny things.
And while the human eye contains about 200,000 visual cells per square millimeter, most birds have three times more, while hawks, vultures and eagles have as many as a million, and possibly more such cells per square millimeter. “Besides, some birds also have additional “aids” – two fowls in each eye – that is, the areas of maximum optical resolution that allow them to estimate the distance and speed accurately. Birds feeding on flying insects are endowed with similar properties. Furthermore, the birds are endowed with unusually soft lenses, thanks to which they can quickly focus their view.
Sensitivity to electric stimulants
Sharks have so-called electro-receptors, which can sense the existence of an electric field just as the ear registers sound. But unlike them, electric fish are also endowed with particular electrical organs that enable them, like bats, to emit sound signals and then accompany their echoes, emitting electrical waves or impulses depending on which type of fish it is, and then with specially, receptors reveal any interference within the generated electric field. Thanks to this, electrical fish can detect any obstacles in front of themselves, prey, and even males or females.
Imagine how this would look like if each of us owned a built-in compass. We would never get lost! But in the body of some creatures, including bees and trouts, scientists have found tiny microscopic crystals of magnetite, an element that is a natural magnet.
Cells containing these crystals in these animals are associated with the nervous system. Because of this, bees and trouts can detect the action of the magnetic field. Bees even use the Earth’s magnetic field – it serves as some kind of orientation when building a hive and for orientation in space.
It is possible that many animals that regularly move to other parts of the world – for example, birds, turtles, salmon, and whales – have a sensation that reacts to the Earth’s magnetic field. However, it seems that the orientation of this animal does not rely solely on it, but is assisted by many different senses. So salmon, to find the river from which it sprung, probably uses its keen sense of smell.
Hearing people envy
Compared to a man, many creatures possess an unusual sensation of hearing. A man can listen to sounds in the range of 20 to 20,000 hertz (titer per second), a dog ranging from 40 to 46,000 hertz and a horse between 31 and 40,000 hertz. Elephants and cattle can even hear sounds within the infrared area (below the lower limit of human ear hearing) to a frequency of only 16 hertz.
As lower frequency sounds travel further, elephants can communicate at a distance of three or more kilometers. Some researchers say that animal reactions with such abilities could even serve as a timely earthquake and storm warning, as both of these phenomena spread infrared waves.
Insects can also hear the sounds of an extensive frequency range, some even hear sounds that are over two octaves higher than the sound that registers the human ear, and the other insects pick a lower pitch.
Some insects hear through thin, flat, umbilical-like membrane that can be found in almost all parts of their body except on the head. Others, like hearing aids, use tiny hairs that, besides sound, also react to the slightest stream of air, such as what causes a human hand movement. It explains why the fly is so hard to hit with a blow!
And now imagine that you have such a good hearing that you can hear when some bug walks by! Such admiration worth hearing has the only flying mammal in the world – the bat. Of course, bats need such a sharp hearing sensation to be able to orient in the dark and hunt the insects by echocardiography or using the sonar.
“Imagine a sonar system that is more sophisticated than the one that is equipped with state-of-the-art submarines. And now imagine that this system uses a small bat that stays in your palm. All the calculations needed to make the bat estimate the distance, speed, and even know which insects he hunts, takes place in a brain that is smaller than our nails on our thumb!
As the precision of echolocation also depends on the quality of the emitted audio signal, the bats “can control the height of their voice so skillfully that opera singers probably envy them” is stated in one manual. Some bats also have a special skin growth on their nose, which, all in all, serve to concentrate the sounds. All of these features make up so sophisticated sonar that a bat can create an “acoustic image” of something as small as a human hair!
Besides bats, there are at least two species of birds that use echolocation technique – Asian and Australian cichlids and South American oilbirds. However, it seems that it serves them only for orientation in the dark caves in which they live.
Sonar at sea
Toothed cetaceans (whales) also uses sonar, although scientists still do not know precisely how. For dolphins, everything begins with the release of the specific cliche sounds that this animal, as it is thought, doesn’t produce in the throat, but in its nasal system.
Then, using a special fat mass on the front part of the head – the so-called melon – it concentrates the sounds in the sound beam, which illuminates the path so to speak.
But how do dolphins hear the sound of those sounds? It doesn’t appear that the ears are used for this purpose, but the lower jaw and associated organs are associated with the middle ear. Interestingly, that part of the dolphin body contains the same type of fatty tissue as melon on his head.
The clicking dolphin sounds are very similar to the mathematical waveform called Gabor’s function. This function proves that dolphin clicks “are almost entirely matched to the mathematical representation of the perfect sonar signal.”
The strength of their sonic click dolphins adjusts from whispers to sounds of the superior power of 220 decibels. How much are 220 decibels? Well, loud rock music can create a noise of 120 decibels, and artillery fire of 130 decibels.
Since the dolphins are equipped with a far more powerful sonar, they can detect such a tiny object as a ball of eight inches in diameter at a distance of 120 meters, and in still waters this distance can be even higher.
Do you feel that this kind of reflection on the miraculous senses endowed with living beings fills you with awe and admiration?