To move, spiders pump and remove blood into and from their legs. Spiders mainly produce silk to spin webs. For spiders, spinning a web is a very difficult procedure. Orb-weavers are the only spiders that spin spiral webs. Funnel web spiders spin funnel-like entrances to their underground or sheltered homes.
Trapdoor spiders make trap doors to catch insects.
Crab spiders hold their legs similar to how a crab would. If a spider can hurt or kill a person or animal it is considered poisonous. Water spiders live their lives under water but still breathe air. That is why spiders are so different and have adapted to the environments they live in to survive. Arachnid Web Pages.