The pinnacle of beauty to most people is a symmetrical face, one without any major left-right differences. But for blind Mexican cavefish (Astyanax mexicanus), asymmetry may be a lifesaver. That’s because their lopsided skulls may help them feel their way along dark cave walls – similar to a person navigating by touch in the dark. That behavior, presented here this week at the annual meeting of the Society for Integrative and Comparative Biology, suggests being a little “off” can have evolutionary benefits.
Lots of cave dwellers are a bit unbalanced. Cave fish tend to have one eye that is larger than the other, for example, and cave crickets have different size antennae. Some researchers wondered whether left-right differences might help these creatures get around.
They scanned the skulls of A. mexicanus fish from three caves in Mexico. Their computerized tomography scans revealed most fish skulls bent slightly to the left, giving the right side of their faces slightly more exposure. Other tests showed these fish tended to drift along the right-hand side of cave walls, presumably using the larger side of their faces to feel their way in the dark. (1)
We have learned that evolution makes things more suitable for survival. And we tend to connect this with perfection. Perfection of mechanisms, perfection of structure, perfection of function. It is this perfection which causes life.
But could it be that we are misled?
Blinded by the light, could it be that we are heading towards the dark?
We like to see order as the foundation of existence. Enchanted by it, we fail to notice that this gift always leads to death.
We like to see perfection as the foundation of life. Mesmerized by it, we fail to see that it is imperfection which leads to life.
It is only the imperfect beings which will live longer.
Do not envy them.
Take a good look.
They are crying in the darkness…
Feel the dark walls of existence around you.
They cry out silently…
Life is not about living!