Wednesday, December 23, 2015
Sydney funnel spider
The Sydney funnel-web spider, Atrax robustus, is an Australian funnel-web spider usually found within a 100 km (62 mi) radius of Sydney, New South Wales, Australia.The Sydney funnel-web spider is unquestionably the most dangerous spider in Australia; the red back and the paralysis tick are the only other two arachnids with potentially fatal bites.The Sydney Funnel-web Spider (Atrax robustus) occurs in New South Wales, from Newcastle to Nowra and west to Lithgow. They especially favour the forested upland areas surrounding the lower, more open country of the central Cumberland Basin.It is a large (6-7 cm), black, aggressive, ugly looking spider with massive fangs. These are large and powerful enough to easily penetrate a fingernail. When disturbed it tends to rear up on its hind legs, a defensive posture that exposes the fangs. The venom of the slightly smaller male spider is five times as toxic as the female. This is unfortunate, as male funnel webs tend to roam about, particularly after heavy rain in summer, and often wind up indoors. The primary toxic component is atraxotoxin, which alone can cause all the symptoms. The venom also contains hyaluronidase and other components (GABA, spermine, indole acetic acid). For some strange reason, human beings (and other primates and monkeys) are particularly sensitive to the venom, whereas toads, cats and rabbits are almost unaffected.