These venomous spiders are usually a ˝ inch in length, with a shiny black body, long thin legs and large oval abdomen. Females typically exhibit a red “hourglass” pattern on the underside of the abdomen, but this is not always the case.
Usually shiny black but may also be various shades of brown or mottled brown and white.
The black widow spider weaves a very strong but formless and erratic web close to the ground and can often be found in drain pipes, under outhouse toilet seats and beneath logs and rocks. The tips of the spider’s legs are oily to prevent it from becoming stuck in its own web. It can usually be found hiding belly up in its web waiting to catch prey.
Both males and females construct webs to capture their prey, which includes flies, moths and crickets and may also consist of reptiles and other small animals. Their fangs inject venom as well as digestive juices into the prey. This method not only kills the prey, but also liquefies its flesh so the spider can eat it more easily.
A female black widow can produce up to nine egg sacs with an average of 300 to 400 eggs in each sac. The sacs are about ˝ inch in diameter and have a smooth surface. The newly hatched spiderlings emerge from the sac and remain close to it for a day or two. Although they are not poisonous, they are cannibalistic and will often eat one another. After a few days the spiderlings climb to high points, release a strand of webbing and propel themselves to other locations in a process known as ballooning.
The black widow spider is the most dangerous North American spider because they inject a neurotoxin when they bite, the effect of which can be serious and even fatal. A bite results in extreme pain and cramping that can take several days to diminish. Many people are bitten when they pick up a log or other item the spider is hiding under.