Facts on Spiders

History

• Spiders have existed for at least 350,000 years. There are approximately 37,000 species of spiders in the world.

Function

• Spiders play an important role in the environment by consuming insects. As a group, spiders eat more insects than birds.

Features

• Spiders are not actually considered to be insects. They are arthropods. Spiders have two main body parts consisting of a combined head, thorax--called the cephalothorax--and the abdomen. The spider has no internal skeleton. The body is covered with a hard outer covering called the exoskeleton.

Identification

• Spiders have four pairs of legs. Most spiders have 8 eyes but some have less. The Brown Recluse spider has 6 eyes.

Significance

• All spiders are carnivorous predators. Most are nocturnal hunters. Spiders can survive for several weeks without food. The Brown Recluse spider has a violin shape on the upper side of the cephalothorax. The Black Widow has two reddish markings that join to form an hourglass shape.

Considerations

• Most spiders live an average of 1 to 2 years, but a male Black Widow lives 4 to 10 years. A female Black Widow can live as long as 25 years. Baby spiders are colorless. Spider droppings are white in color and known as guanine. The silk of a spider's web is liquid until it is exposed to air.

Fun Fact

• The venom of a Black Widow spider is 15 times more potent than that of a Diamondback Rattlesnake, but they inject a minute amount of venom. The most dangerous spider is the Australian Funnel spider.