Jumping spider
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The jumping spiders (family Salticidae) contains more than 500 genera and over 5,000 species, making it the largest family of spiders. Jumping spiders (unlike most others) have good vision and use it for hunting and transportation, capable of jumping from place to place, secured by a silk tether.
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Appearance and habitat
Jumping spiders live in a variety of habitats, including mountains (one species is reported to have been the spider collected at the highest elevation, on the slopes of Mt. Everest). Tropical forests harbor the most species, but deserts, temperate forests, scrub lands, and even the intertidal zone (in Malaysia) can be home. Jumping spiders work like technical climbers in the world of mountain climbing. When a jumping spider is moving from place to place, and especially just before it jumps from one place to another, it tethers a filament of silk to whatever it is standing on. Should it fall for one reason or another, it just reels itself back to the point it secured its "climbing rope."
Several species of jumping spiders appear to mimic ants, beetles, or pseudoscorpions. Others may appear to be parts of grass stems, bumps on twigs, bark, part of a rock or even part of a sand surface.
Some jumping spiders are very shy, while others seem friendly and will jump from fingertip to fingertip, or (be careful!) from fingertip to nose. Unlike almost all other spiders, they can quite easily climb on glass. They also use their silk to weave small tent-like dwellings, where females can protect their eggs.
Vision
Jumping spiders have very good vision centered in their anterior median eyes (AME). These eyes are able to create a focused image on the retina, which has four layers of receptor cells in it. Physiological experiments have shown that they may have up to four different kinds of receptor cell, with different absorption spectra, giving them the possibility of up to tetrachromatic color vision, with sensitivity extending into the ultra-violet range. Color discrimination has been demonstrated in behavioral experiments.
Hunting
Jumping spiders capture their prey by jumping on it from several inches away, and they may jump from twig to twig or leaf to leaf. They can carry out complex manoeuvres such as detours around obstacles in order to reach their prey. Their eyesight is much better than that of other spiders and most, if not all, insects. Most other spiders will only eat prey that they have captured live because they are unable to see dead prey, however some long-legged sac spiders and anyphaenid sac spiders are exceptions as they can recognize insect eggs as food. Jumping spiders, however, will eat flies that have been killed for them.
Venom
Even though they can be quite friendly, the larger ones will bite to protect themselves if you squeeze them. While the bite of a larger jumping spider can be painful, only a few species seem to produce any other effects. Almost all spiders (except hackled orbweavers) have venom, but the venom of most spiders is not worse than the venom of bees.
Reproduction
Jumping spiders also utilize their vision in complex visual courtship displays. Males are often quite different in appearance than females and may have plumose hairs, colored or metallic hairs, front leg fringes, structures on other legs and other, often bizarre, modifications. These are used in visual courtship in which the colored or metallic parts of the body are displayed and complex sideling, vibrational or zigzag movements are performed in a courtship "dance." In recent years it has been discovered that many jumping spiders may have auditory signals as well, with amplified sounds produced by the males sounding like buzzes or drum rolls.