Spider eyes: the superpowers of the organs of vision of animals

Number of eyes in spiders

A striking difference between spiders and insects is the number of legs, there are always 8 of them. This cannot be said about the organs of vision. There is no exact number of spider eyes, the figure is from 2 to 8 pieces. The largest number of species have exactly eight of them, however:

• Caponiidae is a family of small spiders, most of which have 2 eyes. But in the course of development of individuals, the number of eyes may change;
  

  Cute big-eyed jumping spider.

• Symphytognathae, Uloborids have 4 eyes;
• Pipe, Spitters have 6 eyes;
• there are species, mainly inhabitants of dark caves, which are completely devoid of organs of vision.

Features of the organs of vision

Although 2 only 8 eyes have features of work. In order for them to work in unison and give a complete overview, they are separated and have different functions.

primary eyes

Spider eye: 1. Muscles 2. Retina 3. Lens

Primary most often are the main pair, which is located directly. They have edges, clearly defined, but they are motionless. Primary eyes have several functions:

• collection of parts;
• focus on an object;
• image tracking.

The latter is possible due to the fact that the spider's eyes have muscles that move the retina.

secondary eyes

Spider eyes.

They are located next to the primary, can be located on the sides, in the middle or the second row. Their main functions depend on the type of spider, but the general meanings are as follows:

• motion detection;
• hazard analyzer;
• enhance vision in conditions of insufficient humidity.

compound eyes

Not all types of spiders have them, only some have them from their ancestors. The main function is to notice and reflect light. Due to them, there are no blind spots for the animal.

How spider eyes work

The spider's eyes provide them with excellent visibility and good quality of vision. Some individuals are even sensitive to ultraviolet light. Interestingly, the mechanism works the other way around:

• first, the lateral organs of vision are turned on, which see the victim or danger for a long time;
• then the primary eyes are turned on, which focus on the object and analyze, adjusting further actions.

In fact, the spider first catches movement with its side eyes, and then turns to look at a close-up with its main ones.

Rating of sighted spiders

To determine the number of spider eyes, if necessary, you need to know their genus.

Spider eye research

Scientists studied the organs of vision of jumping spiders. It turned out that all eight eyes they have developed from birth and have all 8000 receptors, like adults.

The eyes themselves from the moment of birth of the size that is necessary. But due to the proportions of the body, spiderlings see worse, because they receive less light. As the animal grows, the eyes become larger and vision improves.

Virtues of vision

Spider with 8 eyes.

Spiders, due to their vision, have a lot of advantages over other animals. The advantages are:

• detail is better, weeks in people;
• the ability to view a close-up picture;
• good quality of vision in the ultraviolet;
• the ability to follow prey around;
• precise jumps and movement in the grass, thanks to the ability to determine the distance.

Conclusion

The eyes of a spider are not only organs of vision, but also full-fledged ways of orientation in space. They allow you to hunt, navigate in space, catch the threat and jump. But the exact amount is determined only based on the type of spider.