- Male Sydney funnel-web spider Atrax robustus
- 0.2 gram(s)
- Australia ()
- Not applicable
Defining the term "most venomous" as the most toxic to humans (as some venomous spider species show varying degrees of toxicity to different animal species envenomed by them), the world's most venomous spider is the male Sydney funnel-web spider Atrax robustus. Native to Sydney and its environs within the Australian state of New South Wales, where it can be found in moist habitats including under logs or foliage and frequenting gardens too, in this species just 0.2 mg/kg of the male’s venom is a lethal dose for primates (including humans). The female Sydney funnel-web is far less dangerous than the male, being four-to-six times less effective.