Both predators and prey can be toxic over time

Poisonous and venomous animals aren’t the only ones that can develop this resistance:their predators and prey can, too.The garter snake, which dines on neurotoxic salamanders,has evolved resistance to salamander toxins through some of the same genetic changes as the salamanders themselves.That means that only the most toxic salamanders can avoid being eaten—and only the most resistant snakes will survive the meal.The result is that the genes providing the highest resistance and toxicity will be passed on in greatest quantities to the next generations.As toxicity ramps up, resistance does too,in an evolutionary arms race that plays out over millions of years.This pattern appears over and over again.