Hibernation and Epigenetics


There’s an ancient visceral memory that surfaces and calls to me every year shortly after the winter solstice. This memory runs deeper than any conscious memory, deeper than anything I can pinpoint in my lifetime. It starts with the first night I wake up to the flickering of flames after dozing off while reading or writing. Once that happens, I’m hooked. For the remaining nights of winter, and as often as my 45-year old back will allow me to, I sleep on the futon located about 10 feet away from the warmth of a wood stove’s firebox. As I doze off on a cold winter’s night, a blanket of orange glow soothes me into a deep slumber, permeating the knowledge that no matter how wicked the Ohio winter weather is that night, I’ll be safe and sound. I feel this security in my bones and my cats and dog feel it too. They, like me, barely stir all night long, even as the yips and howls of Mount Air’s coyotes wake us up momentarily.

Sleeping within close proximity of a fire at night meant the difference between life and death for much of our ancestral history. Not only did a communal fire give the warmth needed during cold weather, but it also fended off wild predators. The fear of fire is displayed in most all wild animals and according to scientists, chimpanzees are the one exception to this. Once an animal is able to control their fear of fire, they are one step closer to controlling fire, which brings them one step closer to creating it, a defining milestone in species development.

A 2009 study by anthropologist Dr. Jill Preutz from Iowa State University in West Africa revealed that male chimpanzees performed a ritualistic “fire dance”, similar to the rain dance first observed by primatologist Jane Goodall. Like the rain dance that consists of slow swaying movements by the chimps when thunderstorms approach, the fire dance is aimed at the direction of the fire and also includes exaggerated dance movements. The chimps bark a unique call as a part of the ritual. Additionally, Dr. Pruetz observed that the chimps remained calm when facing the fire at close proximity and were able to predict the fires’ movement far better than she could, even when surrounded on three sides of their encampment.

These observations of chimps in West Africa offer compelling support to a 2012 discovery of charred remains in a South African massive cave called Wonderwerk Cave, located near the edge of the Kalahari desert. The date of the remains has been estimated at 1 million years ago, giving evidence that our human ancestors, Homo Erectus, were capable of controlling and using fire to their benefit. This discovery has caused scientists to change their current estimation of when our ancestors first assumed the control of fire, pushing it back 300,000 years. Adding this many years into an activity that was no doubt repeated each and every day would seem to have the ability to make an imprint into our DNA in ways that we don’t yet understand. If chimps have evolved to not fear fire, it is completely plausible that ancestral humans were in control of fire 1 million years ago.

The topic of whether our genes contain information that is expressed as memory is controversial. However, the field of Epigenetics studies how the human genome reacts to environmental factors. For example, an orphaned child that experiences stress due to the lack of maternal care has a higher level of a chemical than children with attentive mothers. It is likely that this chemical will bind to that child’s DNA, causing the offspring of that child’s genes to express “turned off” or minimized maternal care. And so the offspring lacks a strong maternal “instinct”. Likewise, another set of chemicals that bind to the DNA can allow the protein of the DNA to be more easily picked up during reproduction, resulting in the maximization of that gene expression.

Growing up in a home without outdoor-enthusiastic parents, this information is intriguing to me, as an adoptee who recently initiated a relationship with my birth mother. She and I have had numerous conversations about our love for the outdoors and wildlife, including specifics about how we have spent hours splitting and chopping wood, and heated our homes with it.

So perhaps finding comfort in my orange glow-filled winter “cave” isn’t a direct DNA inheritance from my Homo Erectus ancestors, but it seems plausible that my propensity to sleep near a fire on a cold winter’s night was passed down through my ancestry in some manner. Knowing that I can hibernate safely and soundly on a cold winter’s night is one of my favorite pleasures of life.


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