Poisonous Snakes

I was watching a nature program on PBS and it was observed that poisonous snakes and other poisonous animals tend to be brightly colored. This raises an interesting explanatory question: why make yourself so conspicuous, both to predators and prey? The suggestion made was that some kind of altruism is at work–kindly signaling to others that you are a dangerous character best avoided. But animals don’t engage in this kind of altruism, so why do they signal their presence so rashly? I think the reason is to deter other animals from ganging up on them: it warns other animals to keep away from them, not for their sake, but for the sake of the snake. But why, if the poison is so dangerous a weapon? Because the poison is very limited in supply: the snake cannot kill or incapacitate one attacker after another, because its poison will quickly run out. If a gang forms against it, it will eventually exhaust its arsenal of poison and then become vulnerable to attack. So it tells other animals that it is poisonous and dangerous, as if daring them to attack it. It’s a form of bluster to deter the collective attack: “Don’t even think about it!” But in fact the snake is very vulnerable to group aggression–unlike, say, the lion, which can bite over and over again. Poison is a one-off form of defense. Bright coloring is, for snakes, a complex form of arms-war trade-off.

2 replies
  1. Joe Mckay
    Joe Mckay says:

    A bit like how a man with a gun can control a crowd of people who could overrun him.

    I always think the violence of animals is overrated. Even when they seem to be fighting – it is usually just a struggle to establish dominance. I guess this is because killing an enemy but being badly wounded yourself is as good as being killed. Since there are no A&E departments in the animal kingdom.

    Also – whenever a lion attacks a human being – even if it takes 15-20 seconds before the lion is pulled off the person – it is interesting that the injuries to the person usually only consist of a few scratches and a couple of flesh wounds. Given a big enough size advantage – a lot of people could probably murder another human being in about the same amount of time. In many ways – we are more deadly than lions.

    As such – I am convinced it is easy to intimidate an animal with nothing more than bluff and confidence. Since the animal will only attack if it is sure it can win or feels it’s life is in danger.

    You can see this at work in this remarkable video of tribesmen using nothing more than confident body language to steal meat from a pride of lions.



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