Ground Spiders (Family Gnaphosidae) are common residents of Utah’s rocky landscapes. While they are often found indoors, they are nomadic hunters that prefer to stay on the move rather than waiting in a web.
Ground spiders are strictly ground-dwelling hunters that do not use webs to capture prey.
Nocturnal ProwlersThey spend the day hiding in silk-lined retreats under rocks, logs, or clutter. At night, they emerge to run down their prey with incredible speed.
The "Velcro" SilkWhile they don't build webs, they use their silk to "tether" fast-moving prey to the ground, pinning them down so the spider can deliver a bite.
Indoor SightingsYou’ll likely find them in Utah basements or garages, especially if you have decorative rock or mulch beds right against your home’s foundation.
Are they dangerous?No. Ground spiders are harmless to humans and pets. They are shy and will scramble for a dark corner the moment a light is turned on.
Why do I find them under my boxes and storage bins?Ground spiders love tight, dark spaces. A cardboard box in a garage feels exactly like the underside of a flat rock in the wild.
Do they mean I have an infestation?Not necessarily. Finding one or two usually means they wandered in from the garden. However, if you see them frequently, it’s a sign that their food source (ants and small beetles) is present inside.
