Copyright © 2007 Dorling Kindersley
A large group of eight-legged arthropods, arachnids include spiders, scorpions, ticks, and mites. All scorpions and spiders are meat-eating hunters. Ticks and mites are tiny creatures with sucking or biting mouthparts. Most ticks live as parasites on animals or plants.
Spiders produce liquid silk from glands inside their abdomens. Structures called spinnerets squeeze out the silk, which the spider then pulls into long threads with its legs. Most spiders use silk to spin webs and catch flying prey. Some spiders hunt without using webs.
Scorpions use their pincers to catch and kill prey. They pounce on insects, spiders, and even mice and lizards, then use their pincers to tear them to pieces. The poisonous sting is only used to kill powerful victims that put up a fight. Scorpions hunt at night and use mainly touch and smell to sense their prey.
Almost all arachnids live on land. The class Arachnida includes about 17,000 species, divided into 10 orders: