Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. They are classified in the orders Arachnids, a group which also includes, ticks, mites and scorpions.
Britain has more than 600 species of spiders, all of them harmless to man. There are around 80,000 species of spider worldwide with more being discovered all the time.
The first Arachnid is thought to have been a scorpion like creature from about 500,000,000 years ago.