According to Science News, Modern rattlesnakes have pared down their weaponry stockpile from their ancestor’s massive arsenal. They have lost the need for such a high potency to protect them from their enemies of few. Collection of genes, which probably came about through many gene duplications, coded for toxins affecting the blood, brain and muscles of the snake’s prey. But four million to seven million years ago, some rattlesnake species independently dropped different combinations of those genes to get smaller and more specialized sets of venom toxins. Rattle snakes need to build up antibodies to help keep themselves safe from their own venom, this uses lots of energy and resources therefore if stronger venom is developed then they would practically be dying from energy loss and lack of resources to live from poisonous venom. Its not possible to tell how strong the venom of the ancestral rattlesnakes was but we can say it was sure the pinnacle of nastiness.