Jumping spider is one of the spiders with very sharp vision, and can see prey 10~20cm away. They often open their eyes wide and watch carefully. From the perspective of jumping beads, when you are at a certain distance from it, it will observe you and test whether there is a threat to it. This is also an animal instinct. Because jumping spiders capture prey by their eyesight, the feeling of raising jumping spiders is interactive to some extent, but it is not a mammal after all. Spiders only have a nervous system but do not form a brain system, so spiders have no intelligence, no consciousness, and are just neural instincts.
Jumping spider is the only spider whose eyesight can match that of human beings. If you look at a jumping spider face to face, it will also stare at you with a pair of big eyes, which are commonly referred to as the main eyes, located in the front and middle of the head, to sense size, color and shape. The other six secondary eyes are located laterally and are mainly used to monitor the movement of objects.
The jumping spider is naturally observant. It will not only "jump" to its prey, as its name implies, but also has more than that ability. First, they will see and recognize the prey at a distance of 30 times their body length, and then track it quietly, crawling, waiting and jumping at the same time.
The main eye of jumping spider is as good as that of cat, but its structure is quite different. What we see from the outside is a static corneal lens with a long focal length. Behind each convex lens is a long eye tube leading to the complex retina. Light refracts when it passes through the conical depression on the surface of the retina, which is like the lens of a telescope, producing the effect of magnifying the image. The photoreceptors sensitive to ultraviolet and green light in the spectrum are distributed in four layers. It is believed that the reason why jumping spiders can distinguish colors is that the arrangement of layers and the focusing depth of different wavelengths of light are different.
In addition, the hierarchical arrangement of photoreceptors at the bottom layer enables spiders to aim at objects from far to near without adjusting crystals. There is a small pit in the middle area of the lowest layer, and the receptor is very closely arranged inside. The pit is very small, with only about 100 receptors, forming a visual angle of about 2 degrees. However, in order to make up for this narrow angle horizon, the jumping spider has six muscles attached to the eye canal, so that it can freely rotate and move back and forth. Once staring at the target prey, the eye lens will cast a huge image in the pit, and the jumping spider will monitor it by moving the pit.
Jumping spiders usually trap prey without netting. They have highly evolved eyesight and do not live in the darkness of caves like other spiders. They will actively hunt insects in the daytime.
