Humans and animals’ senses

      Differences & similarities:

 

 

      Animals (under the term ‘animals’ let’s include any living creature as opposed to humans) and humans live in many different worlds that rarely overlap.  Each animal creates its territory and lives inside this territory on its own, inside its own community.  On the contrary, humans move from one cycle (one community) to another.  He can move this year from Japan to Los Angeles, or he may become salesman after abandoning his former profession of dancer.  The animal world is extremely reduced compared to the one of humans.  Animals seldom bother each other and continue basically the same life from birth to death.  At the same time, animals and humans understand little of each other, or at least this is what we presume, but humans have learned to use animals, not the contrary.

Humans understand things animals cannot understand, and animals perceive things humans cannot perceive.  The dog’s nose is a million times more sensitive than ours.  Dogs can hear sounds that humans cannot hear, and from a great distance too.  It is interesting to notice that if the animal senses are more developed, their sense of space is usually much more restricted.  A field for instance would appear like a big forest for an ant.  Ants recognize the obstacles and its height by the vibration on its antennae.  So touching is very important for them, as well as for the housefly that tastes from its feet.

Humans rely a lot on their eyesight.  But again, if humans would like to see like a hawk, they would have to look through binoculars that magnify eight times what they see!

Humans have a sense that help them to recognize where is their right and where is their left, where is up and where is down, where is front and where is back.  Humans have three semicircular canals, in the ear, called cochlea, filled with fine hair and fluid.  When the fluid leaves the base of the ‘cochlea’, hair sense it and gives a signal.  This is what humans call the sense of balance.  In the ‘cochlea’, there are the ‘saccule’ and the ‘utricle’ that contain cells responsible to gravity and tell us which way we are.  Fish orient themselves like humans!  However, insects have fine hair all over their body that plays the same role!

Humans live in a tri-dimensional world:  they recognize three plans:  vertical, horizontal and depth.  Some animals live in a two dimensional world like the water strider, an insect that glides along the surface of the water as if it had air cushion under its feet.  The water strider can perceive only a flat surface of lines:  the horizontal and the vertical dimensions.  If you do the experience of looking at each flat object at the eyes level, you will have an idea of what the water strider perceives.  Therefore, the water strider does not perceive movements coming from above or from under the surface of the water.  It cannot see its enemies, which are birds and fish!  It can only perceive the vibrations at the surface of the water just before being attacked.

Usually animals have a better vision than humans.  Eagles or simple birds can see much better than humans do, and some insects can even see in all directions at the same time.  But many animals do not even need to see; they send sounds into the air or into the water to recognize their surroundings or their peers.  As the sound waves return to them, they know with accuracy what lies ahead and how far.  The bat uses this device as well as the dolphin that lives in rivers.

Some animals, like the snake, orient themselves by changes in temperature.  The snake has a pit organ under its eye that has more than 150,000 heat-sensitive points, enabling it to detect any prey.  Humans have only two or three of them per square centimeter, so they can perceive very little changes in temperature.

Animals like the snail cannot perceive the movement of things.  For it, the grass pushed by the wind is seen like not moving at all.  The reason is that snails do not perceive a movement as a series of movements when the succession of images goes too fast.  And this stage occurs much faster for the snail than for humans.

On the contrary, many animals perceive things that are without motion or change for humans, like the growing of plants.

People can distinguish sounds that range from 15 to 15, 000 hertz (vibrations per second) while dolphins, for instance, can distinguish sounds between 400 and 200,000 hertz.  The dolphin’s language is too fast for humans to hear and too high pitched.

Nevertheless, it seems that humans and animals share one thing in common:  they both are conscious of their environment and are sensitive to it.  Forest monkeys have been reported as shy and nomad. However, monkeys that get used to city life become aggressive bold and always sleep at the same place.  It seems that city life for monkeys as for humans transform them, so that they can never come back to a calmer and simpler life.  They seem to react the same way to stress, in other words to emotions than humans.