Endangered Spider Species

The United States Fish and Wildlife Service protects endangered spiders through the Endangered Species Act. As of 2011, there are four endangered spider species in the United States. For inclusion on the endangered species list, the species must be threatened due to modification or destruction of habitat, overutilization, disease, predation, inadequate regulation methods, or through circumstances, manmade or natural, that affects the survival of the species.

  1. Kauai Cave Wolf Spider

    • Kauai cave wolf spiders exist only in the cave-bearing rock and lava tubes in the Koloa Basin in Kauai, Hawaii. Listed as endangered in 2000, the construction of subdivisions, golf courses, hotel and tourists attractions that surround the habitat cave area threatens the habitat of these eyeless spiders. The planning of additional construction will continue to affect the habitat by changing food and water infiltration, crushing and filling voids and introducing pollutants. Other threats to the Kauai cave wolf spider include their low reproductive rate, making them vulnerable to disease and predators, such as predator worms invading the caves.

    Tooth Cave Spider

    • Native to Tooth Cave, within Edwards Limestone Formation located in Travis County, Texas, the sedentary Tooth cave spider spins its web in the ceiling and walls of this cave. The cream-colored Tooth cave spider has reduced eyesight, even though it has adapted to its dark environment. Listed as endangered in 1988, the limited habitat of only one cave and the threat of local land development classify the endangerment of this spider as critical.

    Spruce-Fir Moss Spider

    • The spruce-fir moss spider lives in high elevated areas on well-drained moist moss mats that grow on rocks and boulders in shady areas. These spiders, endangered since 1995, inhabit six counties in North Carolina, two counties in Tennessee and three counties in Virginia. These light-brown to dark reddish-brown spiders have a yellowish-brown carapace with no abdomen markings. The loss of appropriate moss habitat due to the infestation of the balsam woody adelgid insect infesting the Fraser Fir, primarily threatens the spruce fir moss spider. Other endangerment threats include human trampling of the moss mats, acid rain, previous logging and burning operations.

    Government Canyon Bat Cave Spider

    • Listed on the endangered list in 2000, the Government canyon bat cave spider inhabits only two caves, the Government Canyon Bat Cave and Surprise Sink in the Government Canyon State Natural Area in Bexar County, Texas. The increase of population and urbanization in Bexar County threatens the habitat of this yellow, eyeless spider with short legs. Land developing completely fills in their caves, fills in the cave entrances or quarries away the rock of the caves. Other degradation of the spider habitat results from contamination, excessive human visitors, obtrusive predators and the change in drainage patterns and surface plants.