Spiders are animals with an unusual appearance. To some, they seem frightening, others on the contrary, like them and even contain houses.
In what they do not refuse, so it is in unusual.
Even the number of spider's eyes differs from that of most animals.
Pair of spider eyes
A spider can have a different number of eyes inDepending on the species to which it belongs. Their number can vary from two to twelve. Some arthropods do without sight organs at all. For example, cave spiders, who spend their whole lives in the dark, do not have eyes, since they simply do not need them.
Although most spiders are availableEight eyes arranged in two rows, the sight in the life of these animals plays far from the main role, and, despite such a number of visual organs, they see little. A spider, who can see an object at a distance of thirty centimeters, may already be considered sharp-eyed. However, the vast majority of spiders do not need good eyesight. They weave a web, where they wait for their prey.
The fact that the mosquito or fly caught in their nets, these arthropods learn from the vibration of the web, which creates a fluttering victim.
The structure of the spider's eyes
Numerous visions of the spider do not workThe same. The middle pair of eyes usually has larger dimensions than the extra eyes. The main organs of vision are devoid of mirrors, which reflect sunlight, but they are attached to the bundles of muscles, through which the eyes can move. The lateral organs, on the other hand, are equipped with mirrors, but are devoid of muscle bundles.
Apparently, this is due to the fact that the eyes perform different functions: the forehand in the hunting species follows the prey, and the lateral ones observe the danger approaching.
Eagles among spiders
There is, however, a group of spiders thatHave extremely sharp eyesight. This is a stray spider-horse, which does not sit still waiting for its prey, but actively engaged in its search. The sight of these representatives of arthropods is sharp in comparison with the sight of a man. In addition, they are able to distinguish colors, which is not typical for such primitive animals.
The horses have well developed eye muscles, thatAllows these animals to follow the prey, and the main eyes are equipped with a large lens and somewhat extended in length, like a telescope. The side eyes allow the wandering spider to fix the motion on the side, behind itself and above itself. Despite the fact that the eye of this spider has eight, and they have different functions and show a different picture, together they act as a coherent visual apparatus that ensures the survival of these small animals.