Spiders (order Araneae) are air-breathing chelicerate arthropods. Trapdoor spiders, of family Ctenizidae, are medium-sized mygalomorph spiders that construct burrows with a cork-like trapdoor made of soil, vegetation and silk. The Trapdoor Spider is difficult to see when it is closed because the plant and soil materials effectively camouflage it. The trapdoor is hinged on one side with silk. The spiders, which are usually nocturnal, typically wait for prey while holding onto the underside of the door with the claws on their tarsi. Prey is captured when insects, other arthropods, or small vertebrates venture too close to the half-open trapdoor at night. The spider detects the prey by vibrations and when it comes close enough, the spider leaps out of its burrow and captures it.