Bravo Little Worm

I was reading a book about something totally unrelated to earthworms, yet, that's just what it got me thinking of. Maybe it's because the sidewalk in front of my house is strewn with the crispy corpses of the little guys who didn't make it back to the soil after the last rain.
Anyway, just when I thought worms were about as primitive and boring as a thing could be,I stumble upon something remarkable about them.
Everyone has at some point or another has chopped a worm in half. Whether it be by accident while gardening, or more malicious in nature (i.e. you want to watch them squirm), it is pretty likely you can form in your mind a picture of what happens.
The two pieces of the worm start wiggling around frantically...or do they? I have done a little looking on line, and I have discovered while the tail end wiggles a lot,the head end usually doesn't. The reason for this is because there is some sort of chemical that is produced in the head area of worms which suppresses the action of wiggling. When the head part is separated from the tail the chemical suppressant is no longer able to inhibit the natural writhing motion, and so it convulses.

Isn't that interesting? What's even more interesting is why a worm might have evolved such a chemical in the first place. And if you think about why that might be of great use to a worm, suddenly this odd quality borders on genius. The fact of the matter is a worm head can grow a new tail, but a severed tail cannot grow a new head. So if you cut a worm in half you don't get two new worms. You get one shorter (but will probably live) worm, and one dead tail. Now think about what would happen if say you were a worm that was unfortunate enough to get caught by a bird, and you were snapped in half to be consumed in two bites. At that point you must face facts and wave goodbye to your tail, there is no helping it. But your head part could continue on living (and reproduce) if you could only get away. And what better decoy (or distraction) for a predator than a (now useless) tail jumping and thrashing about? It draws the attention away from the still viable head part of the worm, so it has, at least a small chance of escape! Ingenious I say.
Bravo little worm.
Remarkable isn't it that such an apparently simple animal could have developed such a solution to a problem? Well, maybe the worms didn't develop the strategy, but natural selection did, through the worm.
I have always been the kind of girl who saves worms from puddles, and hot sidewalks, I just never realized how cool a thing I was saving.