Look at a jumping spider, and it will look right back at you with large, forward-facing eyes. The jumping spiders, family Salticidae, comprise the largest of all spider groups, with over 5,000 species worldwide.
Jumping spiders are small and scrappy carnivores. Salticids can run, climb, and (as the common name suggests) jump. Prior to jumping, the spider will attach a silk thread to the surface beneath it, so it can climb quickly back to its perch if needed. Jumping spiders are often fuzzy, and measure less than a half inch in body length.
Salticids, like most other spiders, have eight eyes. On its face, a jumping spider has four eyes with an enormous pair in the center, giving it an almost alien appearance. The remaining, smaller eyes are found on the dorsal surface of the cephalothorax. This unique eye arrangement makes it easy to identify jumping spiders.
Jumping spiders hunt and feed on small insects. All are carnivorous, but a few species also eat some pollen and nectar.
Young jumping spiders emerge from the egg sac looking like tiny versions of their parents. They molt and grow into adulthood. A female jumping spider builds a silk case around her eggs. She will often stand guard over them until they hatch. You have probably seen these spiders with their eggs in corners of exterior windows or doorframes.
Special Adaptations and Defenses:
The size and shape of their eyes give jumping spiders excellent vision. Salticids use this to their advantage as hunters, employing their high resolution vision to locate potential prey. Insects and spiders with good vision often do elaborate courtship dances to attract mates, and the jumping spiders are no exception to this rule.
As the common name suggests, a jumping spider can jump quite well, achieving distances over 50 times its body length. Look at their legs, however, and you'll see they don't have strong, muscular legs. To leap, salticids quickly increase the blood pressure to their legs, which causes the legs to extend and propel their bodies through the air.
Some jumping spiders mimic insects, like ants. Others are camouflaged to blend into their surroundings, helping them sneak up on prey.
Range and Distribution:
Salticids live throughout the world, including the Americas, Europe, Asia, Africa, and Australia. More species live in the tropics, but jumping spiders are abundant nearly everywhere in their range.