Spiders
What are spiders?
Spiders belong to a group of animals called the arachnids. There are about 32,000 known species of spider. They vary in size, shape and habits, but they all have the same basic body structure.
Every spider has two body parts. The front part is called the cephalothorax, is made up of the head and chest joined together. All spider have eight jointed legs attached to the cephalothorax. The second part of the body is the abdomen, or opistosoma. This contains the digestive and reproductive organs, plus the spinnerets which the spider uses to produce its silk.
Most spiders have eight eyes and poison glands, fangs in their jaws, which they use to inject poison into insects. The venom paralyzes or kills their prey.
Why do spiders produce silk?
All spiders spin silk, which is very important to their lives. They use silk for many things, such as to make silk cocoons to wrap their eggs and to keep them safe and warm while they develop.
Spiders can spin different types of silk for different jobs. If the spider needs the silk to make a web to trap its prey, glands near the spinnerets coat the silk with a sticky substance. If a spider needs to travel from place to place, or to anchor its web, it makes dry silk. Other glands secrete substances that can make a silk perfect for wrapping an egg cocoon.
A thread of spider silk is stronger than a steel thread of the same diameter and can be stretched to almost one third of its length without breaking.
How spiders hunt for food?
Some spiders hunt for their food with keen eyesight and fast legs. Poisonous spiders like the most feared tarantula will catch an insect and bite it very quickly. The spiders poison quickly paralyzes the insect leaving it helpless and soon it dies.
A Wolf spider doesn't use a web to catch its prey, it comes out of its home at night and quickly scampers to catch its food.
A Trap Door Spider spins a silky web wall for its home in the ground. It builds a trap door for the roof by mixing thread and soil together. The Spider hides inside the trap door. If an insect comes too close Trap Door the spider opens the trap door and captures the insect by a surprise attack.
Where can they be found?
Although spiders can live almost anywhere in the world, some like it where it is very humid, and some like it where it is very dry. Some spiders live underground and catch their prey by jumping out at them. Others live in trees and capture their prey in their webs. Some can be found in water, grass, trees, bushes, or in our house.