Spiders - animals with unusual appearance. To some they seem frightening, others on the contrary, love them, and even contain the house.
What they can not refuse, so it is unusual.
Even the number of eyes in the spider is different from that of most animals.
Couples spider eyes
Spiders can be a different number of eyes inDepending on the species to which it belongs. Their amount capable vary from two to twelve. Some arthropods altogether dispense with the organs of vision. For example, cave spiders, all his life conducting in darkness, the eyes do not have, because they simply do not need them.
Although most spiders availableeight eyes arranged in two rows, the vision in the life of these animals is not played a major role, and in spite of a number of visual organs, they see weak. Spider, who can see the object at a distance of thirty centimeters, can already be considered a watchful. However, the vast majority of spiders and do not require good vision. They weave a web, where waiting for their prey.
The fact that a mosquito or a fly caught in their nets, these arthropods recognized by web vibration, which creates a flutter victim.
The structure of the spider eyes
Numerous bodies of spider do not workequally. The middle pair of eyes usually has larger dimensions than the extra eyes. The main organs of deprived zerkalets that reflect sunlight, but to them are attached bundles of muscles, through which the eye can move. Side bodies, in contrast, are provided with a mirror, but devoid of muscle bundles.
Apparently, this is because the eyes have different functions: the front at the hunting of species follow the prey, and the side - observe the approaching danger.
Eagles among spiders
There is, however, a group of spiders thatThey have extremely keen eyesight. This wandering spiders, horses that do not sit on the ground, waiting for their prey, and are actively engaged in the search for her. The vision of the representatives of arthropods on the sharpness comparable to the human eye. In addition, they are able to distinguish colors, which is not typical for such primitive animals.
In horses well developed eye muscles thatIt allows these animals to follow the prey, and the main equipped with a large eye lens and a few extended in length like a telescope. Lateral eyes allow wandering spider capture movement from the side, behind and above him. Despite the fact that the eye at this spider eight and they have different functions and display different image together they act as a coherent visual apparatus providing this small animal survival.