Awful Symmetry 2: Hungry Not Evil

This is the first chapter of a short introduction to speculative biology. It was seen first by subscribers, so, you know…subscribe.


I read a book once in which a team of intrepid space archaeologists find themselves menaced by an army of crablike aliens. Each crab is about the size of a basketball, but in a swarm of hundreds, their taste for human flesh cannot be denied!

And there’s the problem. Why would alien predators instinctively attack such exotic prey as humans? And if they did, why would they collect into a swarm in order to obtain a couple hundred kilograms of flesh?

Compare that behavior to real swarms. South American army ants and African driver ants do collect into large mobile colonies and march from one place to another, devouring whatever animals they find along the way. But the mass of the food they collect must be at least a 40% of the mass of the swarm1 and the ants don’t bother to pursue prey or tackle animals that put up too much of a fight. Ant or tiger, for a predator, every attack is a gamble and devoting all your energy to an extended chase after unknown prey is just not worth the effort.

Authors want to make animals malevolent, but just like with human characters, antagonists are more interesting when their motivations extend beyond pure evil. Real animals attack people because they are hungry, frightened, angry, or in some cases, just curious.Those behaviors evolved for a reason, and that reason is the way the animal in question fits into its ecosystem.

So what is your monster hungry for and why?


1Assuming a mass per ant of .001-.005g, a colony population of 100,000-600,000 and given the daily food intake of 38.2g given for Eciton hamatum by Powell, S. Insect. Soc. (2011) 58: 317. doi:10.1007/s00040-011-0152-3

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