Spider, common name for about 34,000 species of arthropod animals having eight walking legs, anterior appendages bearing fangs and poison glands, and specialized reproductive organs on the second appendages of the male. They commonly make extensive use of silk that they spin. Like other arachnid species, spiders are terrestrial, although a few have adapted to freshwater life by trapping air bubbles underwater and carrying the bubbles with them. Spiders are numerous and occur worldwide. Although most are less than 1 cm (less than 0.4 in) long, the largest has a body length of about 9 cm (about 3.6 in), and spider leg spans can be much greater.
Spiders are small, eight-legged creatures that are best known for spinning silk webs. Spiders spin webs so they can catch insects for their food and even larger and stronger insects cannot escape.
All spiders spin silk but some don't spin webs. Bolas spiders spin a single line with a sticky end. Any insect near, gets trapped when the spider swings the sticky line near them.
All spiders have fangs and most kinds have poison glands. They use their fangs and poison glands to capture their food. A spider's bite can kill insects and other small animals. A few kinds of spiders are harmful to human beings. In North America, six kinds of spiders harm people, they are - the Brown Recluse, Sac, Black Widow, Brown Widow, Red-legged Widow and the Varied Widow. Four of the Widow females are known to bite humans. The bites of these six spiders often cause mild reactions. Usually a person irritates a spider several times for it to bite you. In Australia, the most dangerous spider is the Funnel-Web with the Red-back, a type of Black Widow spider, also being dangerous.
Spiders are helpful to people because they eat harmful insects. They eat grasshoppers and locusts which destroy crops. Spiders also eat flies and mosquitoes which carry diseases. Spiders feed mostly on insects but some capture and eat tadpoles, small frogs, small fish and mice. Most females are larger and stronger than the males and occasionally they eat males. Spiders can live anywhere they can find food like fields, woods, swamps, caves and deserts. One kind of spider spends most of its life underwater. Another kind lives near the top of Mount Everest, the world's highest mountain. Some live in houses, barns, and other buildings. Others live on the outside of buildings, on walls, windscreens and corners of doors and windows.
Types of Spiders:
The cellar spiders
The comb-footed spiders
Ogre-faced stick spider
Whip or tailed spiders
Bolus or angling spiders
Magnificent spider (type of bolus spider)