Jumping Spider

The common name comes from their jumping ability and habit, which they use to capture prey. They are an occasional nuisance pest indoors, and some black-colored species may cause concern when people mistake them for black widow spiders. About 300 species are found in the United States and Canada.

Recognition

Adult body length is about 1/8-3/4 inch; robust, compact with relatively short legs. With eight eyes in third rows. Front row or four eyes with middle pair very large, third row of two moderately large eyes at about midlength of cephalothorax, and middle row of two small eyes about midway between first and third rows. Color usually black, sometimes brown, tan, or gray, and usually with pale markings of white, gray, yellow, red, blue and/or green; typically densely covered with hairs or scales, which often are brightly colored or irridescent. Front legs usually thicker and somewhat longer than other legs; terraces with two serrate claws each. No snare webs, quick to jump, with jumping power generally supplied by the fourth pair of legs.

Note that there are three genera with species which mimic ants, having cephalothorax slightly pinched in at middle to resemble head and thorax and front legs held up and bent like elbowed antennae. These species do not jump.

Habits

Unlike most spiders, jumping spiders are active during the daytime and seem to like sunshine. They are hunters and have the keenest vision of all spiders, being able to detect and react to movement up to 18 inches distant; however, their night vision is very poor. They can move rapidly sideways and backwards for short distances.

They are excellent jumpers. They either jump on passing prey, or when they locate prey, it is stalked and then pounced upon. When hunting they may jump 1 inch or more, but when threatened, they may jump 20 times their body length. They employ silk as a dragline when they jump; the dragline is anchored before they jump and acts as a safety line.

Retreats may be built under furniture, in drapery folds, between books on bookshelves, in cracks such as found in wood floors, around door and window moldings, etc.

Indoors, they usually will be found hunting around windows and doors because more insects are attracted to these areas. Also, their vision is best in sunlit areas.