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.
Conus geographus
The geography cone is highly dangerous; live specimens should be handled with extreme caution. "C. geographus" has the most toxic sting known among "Conus" species and is responsible for more than thirty human fatalities. Yoshiba estimated an LD70 value (in humans) of 0.001-0.003 mg/kg. In two cases of envenomation, only 0.0002-0.0005 mg resulted in severe paralysis. Other figures estimate LD50 values of 0.012-0.03 mg/kg. These estimates make the geographic cone snail the most venomous animal in the world. The venom is a complex mix of hundreds of different toxins that is delivered through toxoglossan radula, a harpoon-like tooth propelled from an extendable proboscis. There is no antivenom for a cone snail sting, and treatment consists of keeping victims alive until the toxins wear off.
Among the compounds found in cone snail venom are proteins which, when isolated, have great potential as pain-killing drugs. Research shows that certain component proteins of the venom target specific human pain receptors and can be up to 10,000 times more potent than morphine without morphine's addictive properties and side-effects.