What Is a Spider Spiders live almost everywhere on earth from seashores swamps and jungles to subways basements and shopping centers Spiders live as near to you as the corner of your clothes closet or the drain in your bathtub They also live as far from you as the Arctic tundra or the slopes of Mount Everest Young spiders have even been discovered floating on air currents 16,000 feet above the earth Those who study spiders are careful as to what general statements they make about them This is because spider behavior can vary from one part of the world to another Two spiders of exactly the same kind may behave differently if one lives in Montana and the other lives in Moscow Close observation of spiders in their natural environments is the best way to come to know them black-and-yellow argiope Argiope aurantia
Three hundred and ninety-five million years ago warm shallow seas covered much of the earth Jawless fish swam in the water and giant ferns grew on the land In that distant time called the Devonian era the first spiders appeared Today spiders are one of the earth’s most successful animals There are so many varieties of spiders it is not easy to keep track of them all of tarantulas alone there are 800 different kinds As many species of spiders live just in the state of New Mexico as there are bird species in the entire United States South American bird-eating spider Cyrtopholis species barn spider Araneus cavaticus
Spiders are not insects though their jointed legs make them look as though they were Spider bodies and insect bodies are different in important ways Spiders have eight legs while insects have six Spiders have only two distinct body parts insects have three All insects have antennae and most have at least one pair of wings but spiders have no wings and no antennae Only spiders have silk glands and spinnerets at the rear of their abdomens Spiders belong to a group called Arachnida animals with four pairs of legs no antennae or wings and only two body parts Scorpions mites and daddy longlegs are other arachnids They are cousins of spiders but they are not spiders daddy longlegs sarcoptid mite scorpion
All spiders make silk although they are not the only animals that can do this Many insects in larval stages like bagworms silkworms and caterpillars use silk from their mouth glands to spin themselves cocoons It is spiders everyday use of silk through all stages of their lives that sets them apart from other silk makers in the animal kingdom bagworm tent caterpillars silkworm
