The California Trapdoor Spider constructs and lives in a silk-lined burrow, which is a vertical hollow tube up to about 3/4" wide and 8" deep. At the top is a D-shaped hinged lid, which fits very tightly into the opening. The door is kept closed most of the time. If a prey item (insect or other arthropod) comes close, the spider captures it and takes it into the burrow. The female never strays far from her burrow.

In the Fall, males wander around looking for females. After mating, the female lays a batch of several hundred eggs, and after the spiderlings hatch she cares for them and feeds them over the first winter. Then they leave and make their own burrows. Trapdoor spiders are sometimes attacked by parasitic wasps, or by small mammals that dig up the burrows and eat the spiders.