Answer:
~ Venom tends to contain mixtures of protein-based toxins, often acting synergistically to wreak havoc on internal organs. A snake haemotoxic venom might contain one component that prevents blood from clotting, and another that breaks down the walls of blood vessels.
~This "fact" is actually an exaggeration, but it is true that some sea snakes are incredibly venomous. So are certain land snakes: a single bite from an inland taipan contains enough venom to kill 250,000 mice, for instance. And it is not just snakes that hold this sort of power. One drop of marbled cone shell venom can kill 20 humans. A box jellyfish sting can cause cardiac arrest and death in a matter of minutes.
~The reason for an animal possessing toxic weaponry is simple enough. Venom is a means by which to subdue prey without risking your own neck in the struggle. Secondarily, it is also a useful defensive strategy.
~It is reminiscent of the commonly held myth (and it is a myth) about daddy longlegs; namely, that they possess the most powerful venom known to man, but evolved it for nothing because they lack the means to administer it. The most powerful venoms just seem to make no evolutionary sense.
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