09 May 2008

Calvin's 500-story gastropod


Calvin and Hobbes by Bill Watterson

Deniz sent this comic a few days ago. I forwarded it to some friends. Megan e-mailed back this response: "Being a slug on the usual scale, capable of navigating, climbing up, and squirming through a miniature natural neighborhood, would be much more enjoyable than being a monstrous slug on the scale of a city block!" I am not sure if I agree with her. There could be some satisfaction to be had from coating an entire city with slime.

But the real question is "Can a snail or slug grow that big?" And the answer is no. First, I can't think of an adaptive reason for the evolution of a monstrous gastropod from much smaller ancestors. Second, a 500-story snail would need to consume a heck of a lot of calcium carbonate to build itself a decent shell. Third, whenever and wherever such a humongous gastropod crawled, it would lose, in the form of mucus, a heck of a lot of water. Now, imagine a population of such behemoths. They would scrape down hills of limestone, drink up lakes full of water and eat up an entire tropical forest in one afternoon. The next day, they would run out of resources and be extinct by the evening.


4 comments:

John said...

The hypothetical 500-story snails sound a lot like humans, then.

xoggoth said...

Strangely, I once wrote a story on just this topic

http://www.xoggoth.org/pages/xoggoth10.html#worm2

Megan said...

OK, I'll agree that sliming the broad, pillared streets of mid-town D.C. could be fun. The trick is hauling one's massive slug body beyond the borders of D.C. (or to a quiet spot in Rock Creek Park) before the national guard arrive!

Dave Coulter said...

Boy, I sure do miss Calvin & Hobbes!