The world is full of many tiny creatures besides insects. There are snails and slugs that creep along the ground, worms that burrow underground, and many more. Some, like insects, belong to a huge group of little creatures called arthropods, which also includes spiders and other arachnids, centipedes, and woodlice. Scorpions detect their victims through vibrations in the ground - then tear them apart with their pincers. Arachnids Arachnids are small, scurrying creatures that look a little like insects, but they have eight legs, not six, and their bodies have only two parts.
Arachnids also have a pair of 'arms' called pedipalps and a pair of fangs called chelicerae.
There are over 70,000 different kinds of arachnid, including spiders, scorpions, harvestmen, ticks and mites. Spiders are found in nooks and crannies almost everywhere in the world. They are most abundant where there is plenty of vegetation, but you can encounter spiders in the darkest cellars and down the deepest mines, as well as high on mountains. Unlike other hunting animals, spiders generally have poor eyesight. They usually have eight simple eyes, not the compound eyes of insects, and hunt by 'listening' to vibrations in the ground, which they pick up with their legs.