Spiders have eight legs and an exoskeleton of two distinct body regions. Young spiderlings emerge from the egg sac and molt a total of four to twelve times, increasing in size with each molt. Most spiders live one or two years.
Living in a wide variety of habitats, spiders use many techniques for attracting, finding and capturing prey. As predators, spiders liquefy their food before eating by injecting digestive fluids into the paralyzed prey and then sucking it dry.
Benefits to humans- In addition to reducing local disease-carrying insects, spiders provide humans with other medical benefits. Spider venom is used in neurological research and may prevent permanent brain damage in stroke victims. The silk produced by spiders is used in many optical devices including laboratory instruments.