Spiders, crustaceans and insects all belong in the phylum Anthropoda. Spiders, mites, ticks, scorpions and harvestmen make up Arachnida. The difference between spiders and all other arachnids is they have bodies divided up into an abdomen and cephalothorax.
Approximately 43,000 species of spiders have already been discovered, but there are still other species of spiders that have not been discovered yet. Spiders feed on prey that are still alive, using camouflage and burrows to hide from their prey before they attack. Spiders have numerous enemies, including birds, other spiders and wasps. Some species of spiders have excellent eyesight, while others have a good sense of touch that assists them in feeling vibrations from their predators.