Eastern diamondback rattlesnake
The eastern diamondback rattlesnake is the most dangerous venomous snake in North America. While not usually aggressive, it is large and powerful. Its bite has a mortality rate of 10–20% when untreated. The estimated human lethal dose is 100–150 mg. A doctor described one case in which the symptoms included pain, bleeding from where the snake bit the person, internal pain, bleeding from the mouth, hypotension, a weak pulse, swelling and discoloration of the limb that was bitten.