Spiders have long been one of the most successful groups of animals on Earth. Since they first appeared nearly 360 million years ago, they have been major contributors to land-based ecosystems and today they play a vital role in the unique and complex wildlife systems that make up the Australian environment.

Although generally considered drab, repulsive and hairy, spiders display a remarkable array of body shapes and colours. Some are delicately fragile - others range in shape from spherical to triangular, hexagonal or square. They are often beautifully patterned with reds, blues, greens and yellows, or adorned with silver, gold and iridescent colours that vary with changing light.

There are 35,000 known species of spiders worldwide and more than 2000 of these live in Australia. It is estimated that this is only one quarter of the number that actually exist! Australian spiders range in size from the 55mm-long whistling (or bird-eating) spiders to litter-dwelling species that measure less than a millimetre in length.

Spiders belong to a class of arthropods called "arachnids", named after the maiden Arachne from Greek Mythology. The fable tells, she was a skilled weaver who was changed into a spider as punishment for her pride. The class Arachnida also includes scorpions, pseudoscorpions, harvestmen, mites and ticks, but only spiders belong to the order Araneae within this class. Spiders are often confused with insects, which are unrelated and belong to the class Insecta.

The first spiders were probably remarkably similar to many which survive today. They were large, drab, ground-dwelling creatures, probably living in shallow tunnels lined with silk. While these early spiders did produce silk, it was not used to its full benefit until millions of years later when web-making techniques evolved. The most ancient group of living spiders (called Hypochilomorphs) still survive today in eastern Australia and Tasmania, part of our remarkable spider fauna.

This fauna includes many species that are found nowhere else. Spiders range from deserts to caves, streams to seashores and alpine country to rainforests. Most of the species that live in Australia are restricted to Australia but some are also found overseas and several species have been introduced from Australia to other countries.