I don't know about the rattlesnake being the most dangerous snake on the American continent, I live in Central America and the general idea here is that the most dangerous, most aggressive and deadliest snake is the Fer-de-Lance better known as Barba Amarilla or Yellow Beard, by the way we also have rattlesnakes here but the Fer-de-Lance is the most feared and in second place I think I would place the Coral snake. I'm just speaking for Central America I do not even know what they have in South America.