Giant House Spiders

Scientific Name

Eratigena atrica


The most obvious characteristic of the giant house spider is its size. Adult males can can have up to a 4-inch leg span, and female leg spans may be up to 2 inches. The giant house spider is typically dark orange, brown or beige. Their abdomen is mottled in brown, beige and gray and appears to have no banding of the legs.

Behavior, Diet & Habit

When these spiders are seen inside homes they usually are somewhere on or close to the floor, but they can also be found on walls, ceilings, in cabinets, tubs, showers and the dark corners of basements. When found outside around human structures, it is often in darker areas, such as flower beds, under logs, rock piles and other sheltered sites. Giant house spiders normally remain inside their web during the day since they are actively waiting to pounce on a prey spider or insect that comes close to its web after dark.

An interesting relationship exists between giant house spiders and the more infamous hobo spiders. Field professionals have noted that giant house spiders help to prevent hobo spiders from becoming established inside homes and businesses. They do this by out-competing hobo spiders for prey and preferred living space, and male giant house spiders often kill male hobo spiders.


Giant house spiders mature in the summer or fall and mate shortly thereafter. Males and females cohabitate and mate over a period of several weeks. Eventually, the male dies and is eaten by the female. Giant house spider females spin sheet-like cobwebs into where the female typically constructs one or more egg sacs during her lifetime. Each egg sac will contain from 40-50 eggs; however, only about 1-2 percent of the spiderlings that hatch will survive to reach adulthood.

Signs Of An Infestation

Actually seeing these spiders in unacceptable numbers is the most obvious sign of an infestation. Normally, these spiders are seen in late summer through early fall when the males emerge from their normal shelters to look for females with which to mate.


This species is originally a European native that was introduced to southern British Columbia in the early 20th century. Since then, the giant house spider has spread from British Columbia to Washington and Oregon. There are records of small numbers of this spider being found in Alberta, Newfoundland, Nova Scotia, Quebec and Saskatchewan, probably the result of accidental transfer by people moving household goods.

More Information

Sealing all cracks, gaps and crevices that provide access inside the home is an important way to prevent giant house spiders from wandering into the structure. Using a vacuum or broom to remove the spiders, webs and egg cases, and making sure the giant house spider’s food sources are kept to a minimum and harborage sites are removed and cleaned up are also important prevention measures.

Should the homeowner need help controlling these or any spiders, contact your pest management professional and request an inspection. Your pest management professional can then use his or her inspection findings to prepare a comprehensive pest management plan that will effectively and efficiently deal with the specific pest problem.

The giant house spider often is confused with hobo spiders. While there is no definite way to distinguish the two at a quick glance, giant house spiders tend to be more yellowish in color, with distinctive black stripes on the abdomen and full-grown adult hobo spiders are much smaller.

Normally, bites from the giant house spider involve pain equal to a bee sting. The pain is usually localized and lasts for a matter of hours, or at worse less than 1-2 days.