Also called "deep crawlers" by the dwarves, they originally grew in the depths of the dwarven Deep Roads, once having been encouraged by the dwarves to multiply to feed on the numerous species of large bats that the dwarves considered pests. Once the Deep Roads were lost to the darkspawn, these spiders began to feed on genlocks as well as bats, and their numbers were no longer controlled. Some moved up to make their lairs in the surface forests, but most have remained below ground living in caverns or in lost thaigs.
There are many varieties of spiders with the queen being at the center. Her offspring are called spiderling in early states of development. The most dangerous varieties are considered to be the giant poisonous spiders.