The Sydney funnel-web spider is a spider unique to the urban regions of Sydney, Australia. It is also found in other regions of Australia with moist climates and thick vegetation, and has been spotted as far away as the UK, though it is not typically as widespread as other Australian species of spider. The Sydney funnel-web is one type of over 700 different species of spiders worldwide that build funnel-shaped webs in which to trap prey. Of the two genera of funnel-web spiders found in Australia, 40 individual species exist, and the Sydney funnel-web spider is of the Atrax genus known as Atrax robustus.
There are no distinct markings on a Sydney funnel-web spider to identify it, but it is generally completely black, and quite large, similar in size to a small tarantula at up to 3 inches (7.8 centimeters) in length. While some funnel-web spiders make their homes in tree branches, the Sydney funnel-web spider lives entirely on the ground. The primary range for the species is within about a 62-mile (100-kilometer) radius of Sydney. The female of the species is larger than the male, though the male has longer legs, and females remain in their burrows during most of their lives, which can last for up to 20 years.
Among venomous spiders of the world, the Sydney funnel-web spider is considered to be possibly the most dangerous. Males frequently roam in the open in the summer and fall months of November to April in search of mates and can be quite aggressive, openly confronting anything that crosses their path. When challenged, a Sydney funnel-web spider will rear up on its hind legs and make sudden lunges forward to try to bite whatever is in its way.
Despite their deadly nature, it is rare to see Atrax robustus out in wide-open spaces or on grass-covered lawns, since they prefer rocky regions and areas of rotting logs and bushes. Since they are attracted to water, this often causes the spiders to fall into swimming pools in urban areas. They can survive for over a day, however, even if submerged by utilizing air bubbles trapped in hairs under their body to breathe.
Their bites are known to be lethal if not treated quickly with anti-venom. The bite of a Sydney funnel-web spider is extremely painful, and, within 10 to 15 minutes of being bitten, severe side effects such as rapid heart rate or coronary arrest, difficulty breathing, tremors, and vomiting can occur. No one has died from the bite of a Sydney funnel-web spider in Australia since 1981 when anti-venom treatments were developed, but medical authorities still caution that anyone bitten should bandage the area and attempt to keep it still to slow the spread of the venom, while a poison control center is immediately called. Children are especially vulnerable to the spiders, and medical attention in all cases should be sought without delay.