Having a trapdoor on your house is just one technique spiders use to get food. Some types of crab spiders hide on flowers the same color as their bodies. Crab spiders wait camouflaged simply as a part of the plant. Some crab spiders can change their color gradually over two or three days camouflaged by their hiding places. Crab spiders can walk forward, backward, and sideways just like a crab.
Scientists know very little about spider venom.
Among all spiders, poisonous spiders are the smallest in number. Many of the Mygalomorph family possess dangerous poison. Poisonous spiders kill by injecting their prey with venom that could paralyze or kill. Poisonous spiders live all over the world. Poisonous spiders possess poison to kill their prey.