Yesterday, I argued that we should be thankful for flies, in part because we could have ended up with worse things like flying, carnivorous spiders. Überblogger Tim Eisele commented,
The thing I'm grateful for is that something like starlings haven't evolved into aerial piranha. It would be a real bummer to be walking down the street, minding your own business, and then suddenly have a flock of piranha-starlings descend on you and skeletonize you in five minutes flat.In the office, this led to a lively discussion about such things. Could piranha-starlings prevent Mankind from developing an advanced civilization? More generally, what would happen if the dominant carnivore was fast and omnipresent?
First off, in the case of avius pisces chainsawus, you'd never be able to cross an open field unless you had armor or guns. (Even the guns would be of dubious value.) If you couldn't cross open fields, how would you ever get to the point where you made armor in the first place? Human colonies would have to be mostly underground or in places where there was shelter from the Flying Death. Yes, you could start underground and then move aboveground with buildings, like the malls in Toronto that have covered walkways for Winter use, but that comes with it's own dangers like the easy spread of diseases. In effect, the flying piranhas would channel you into an enclosed spaced where microbes could wipe you out, just like the Cliff Dwellers of the American Southwest.
Chalk up another lucky break for us that God decided to lay off making winged Makita sawsalls.
Sometimes I think the only thing that saves us from unstoppable uber-predators is the fact that if a predator is too good, it eats all of its prey and then starves.
ReplyDeleteI suppose that what would actually happen with the piranha-starlings is that they would eat up all of the large surface-dwelling animals, but then wouldn't be able catch enough smaller animals to sustain their big flocks and would have to break up into small groups or individuals to be able to feed themselves. They'd probably end up eating each other. Of course, by that time all of the animals bigger than, say, a rabbit would probably be gone . . .
Tim, do you suppose that's how the dinosaurs died out?
ReplyDeleteI suppose it could have been a factor. Maybe after the asteroid hit Mexico, it knocked back the forage enough that the big herbivores were stressed and slowed down due to lack of food (and maybe also short of cover because the trees died back), allowing the big carnivores to eat them all. Followed by the carnivores eating everything else they could catch. And then each other.
ReplyDeleteI suspect that these ultra-violent planets that science fiction authors are so fond of, where everything is savagely trying to eat everything else and the expected lifespan of an explorer is measured in seconds, just wouldn't be stable conditions and won't actually be found in real life.
Aren't humans the "unstoppable uber-predators" of Earth?
ReplyDeleteWell, sort of. But humans aren't obligate predators; our tendency to devour the wildlife is almost incidental these days, and we wouldn't starve (or even really be particularly affected) if there was nothing to hunt at all.
ReplyDeleteI've seen it argued that, once we developed agriculture, the effect of humans on the environment became more that of an aggressively invasive plant than of a predator. We basically push aside other plants (and whatever feeds on them or lives in them) and replace them with our crops.
Tim, that invasive plant analogy is terrific! I'd never thought of that.
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