Normally spiders are harmless and bite only when they are threatened, for instance by being trapped.  A potentially dangerous spider that is commonly found all over Australia and should be avoided is the Redback spider. Redbacks are found in close proximity of human houses and build their webs in sheltered areas such as sheds, toilets and stores. Female Redbacks are easily identifiable due to the prominent red stripe on its abdomen. The venom of Redback spiders are toxic to humans and cause severe pain. Due to many store workers getting bitten by Redbacks sydney acres real estate companies are often requested to eliminate the spider populations in stores.