Inland taipan
The inland taipan is the most venomous snake in the world. Based on the median lethal dose value in mice, its venom, drop for drop, is by far the most toxic of any snake – much more so than even sea snakes – and it has the most toxic venom of any reptile when tested on human heart cell culture. Unlike most snakes, the inland taipan is a specialist mammal hunter so its venom is specially adapted to kill warm-blooded species. It is estimated that one bite possesses enough lethality to kill at least 100 fully grown men, and, depending on the nature of the bite, it has the potential to kill someone in as little as 30 to 45 minutes if left untreated. It is an extremely fast and agile snake that can strike instantly with extreme accuracy, often striking multiple times in the same attack, and it envenoms in almost every case.
List of medically significant spider bites
The Australian funnel-web spiders, such as the Sydney funnel-web spider "Atrax robustus" (a mygalomorph spider not to be confused with the araneomorph funnel-weaver or grass spiders) are regarded as among the most venomous in the world. They react vigorously to threats and, reputedly, will more often attempt to bite than run away. "A. robustus", a large black spider, is found within a radius of about 100 km from Sydney. Its venom contains a compound known as atracotoxin which is highly toxic to primates. Approximately 10% of bites lead to serious symptoms for a total of 3-4 severe envenomations annually.