The frozen hatchling

The coin next to the hatchling is a penny.

The painted turtle of the upper midwest has an amazing technique designed to enable its hatchlings to survive the below freezing temperatures of their climate--they can completely stop their blood flow.

Now, this technique only works for the very young. Less than a year old, to be exact. Mom's bury their eggs deep into the soil, and when the baby hatches, it can start its journey away from the nest, or it can overwinter there and start it the next spring.

Many decide to wait it out, apparently, safe from predators--but not from freezing temperatures that invade the nest before spring arrives. When temps fall to 26 deg F., first an icy coat forms on their skin. This "freezing" then moves inwards, stopping their blood from circulating--eventually even stopping the blood flow between the heart and the brain.

Amazing, isn't it? That a biological organism can not only survive a complete lack of blood flow to the brain but emerges completely uninjured by this anoxic state. Is this adaptation a sign of sophistication or of simplicity? And, what does that say for humans, who can't survive a mere minutes without oxygen to the brain?

Is our vulnerablility to anoxia really a sign that our brain/circulatory system is more evolved than even that of painted turtles? Or is it nature's way of contributing to culling the population of the most destructive species from nature's repertoire?

And, does the hatchling's ability to revive itself and carry on with the day to day business of survival and reproduction, even after depriving its brain from circulating oxygen, point to the existence of imprinted instructions, permanently embedded in the genetic material of brain tissue itself, rather than in the dynamic biological and chemical processes occuring in the oxygenated state? Instructions that express themselves regardless of sustained exposure to hostile and freezing environments.

That idea only leads me to also ask how many human behaviors are also pre-ordained by "instructions" embedded in the human organism's genetic material and biological tissue. Instructions that express themselves regardless of nutritional intake, economic class, education, etc. It also makes me ask whether certain genetic maps within a species possess the genetic code for certain actions that the map for others in its own species lack. Which of our actions are expressed because of instructions embedded in our genetic material? Do certain of us humans, perhaps with a certain genetic tidbit that other humans lack, have instruction to generate certain enzymes and hormones that lead us to express violent acts, or compassionate acts, or take risks, for example?


An adult grows to 4 to 9 inches.

Thanks to J37ib (top photos of hatchling) and to D. Gordon E. Robertson (photo of adult Chrysemis picta marginata, after text).