These particular nitwits can breed only at sea level because their heads are so light that if the gravity were even minutely less (as at higher altitudes), they would drift away into space like balloons. Their existence is a delicate one however, for should the atmospheric pressure rise above 1 atm, they would be crushed because they are so thin-skinned and have no real backbones.



I am sorry, I must have, ummm, lost the link to the story.

Or something

B