The Trapdoor Spider (Bothriocyrtum californicum) is a stocky, medium-sized to large spider with a thin covering of hair. Mostly nocturnal, it nests underground by constructing a burrow with a trapdoor made of soil and vegetation and hinged with silk. Common in the southwestern United States, its color ranges from yellowish brown to black; it has eight legs, eight eyes (two in the middle and three on each side), and can run very fast. 

These unique spiders will feed on insects that venture too close to the trapdoor. They have also been known to eat frogs, baby snakes, baby birds, mice, and even small fish. Though venomous, a bite from a Trapdoor Spider is not dangerous to humans; however, their bite is very painful. Be very careful when encountering a Trapdoor Spider in the wild. 

To see more photos of the Trapdoor Spider and its burrow, please visit the School of Biological Sciences, University of California, Irvine.