Eastern Diamondback Rattlesnake, common in Florida and the Southeast. Ross Allen has "milked" or extracted venom from hundreds of thousands of these to help make antivenin. Read about how fast these snake can strike in my book.
Sixteenth deadliest snake in the world: Eastern Diamondback found in Southeastern United States. This is the largest venomous snake in North America, and featured on early American flags "Don't Tread on Me"
The Diamond back rattle snake is the deadliest snake in North America. With enough venom to kill 20 men not many recover from bites. The rattle snake can lunge at you with a speed the speed you can see.