the kingsnakes without these venom resistance traits had been killed by vipers that they tried to eat, and only the resistant ones remained. On the other side, vipers that had venom with toxins that were, for example, slightly more painful or fast-acting, might have been more likely to survive a predatory attack. Thus, the arms race escalates. Vipers also exhibit When vipers were first evolving their front fangs, defensive bites became a new option for them. At first, their predators were probably not very good at resisting the effects of the venom, especially if the predator’s physiology was similar to that of their prey, and venom would have made a very good defense mechanism. Vipers would sometimes be killed and eaten, but many predators later died from theirkingsnakes from Florida & the Gulf Coast was the most effective at neutralizing the venom of copperheads & cottonmouths. Mole Kingsnake ) blood is about 75% as effective at neutralizing Mojave Rattlesnake () venom as the blood of Eastern Kingsnakes. Gray-banded Kingsnakes () have moderate neutralization potential against Western Diamondback () venom, but none against Eastern Diamondback () venom. Blood from milksnakes (formerly all called) from various locations had intermediate neutralization capacity, with blood from North American milksnakes being about 70% more effective against rattlesnake venom than blood from Central American milksnakes. Another study found that an eastern milksnake injected with copperhead venom died, and one injected with pigmy rattlesnake venom had "no noticeable ill effects", but a lack of replication prevents these results from being particularly meaningful.