A Long Winter’s Nap: Humans, Hibernation, and Some Really Old Bones

Winter offers endless delights: sledding and snow forts, animal tracks criss-crossing the snowy forest floor, and countless excuses for hot chocolate. But the delights often come with biting wind and painfully cold fingers. Winter can become too much of a good thing, and many of us are eager for spring far before it arrives.
Some animals, like groundhogs, bats or bumblebee queens, skip the season altogether by hibernating. They nestle down in the fall and get ready for a season of inactivity by dropping their body temperature, metabolism, and breathing and heart rates. This allows them to conserve energy—their body fat, as long as they have enough of it, provides them the energy to survive until spring.
So it intrigued me to learn about hibernating humans. Humans! They were a different species from us Homo sapiens (Neanderthals? Homo heidelbergensis? That part’s still being worked out), and they lived over 400 thousand years ago in northern Spain.

Skulls from study site (Sima de los Huesos, northern Spain)

 

The fossilized bones of these ancient humans show patterns similar to those on bones of other hibernating animals. (Like those of the cave bear they found close by!) It appears that bone growth was interrupted each year while these early humans slept the winter away in caves. The fossils also indicate that they were hard-hit by diseases common to hibernating animals, such as kidney disease and bone deformations.
But it’s always been assumed that humans CAN’T hibernate. We’re too big, we need too much food, and we evolved in hot climates that wouldn’t require us to sleep for months at a time. And unlike hibernators, our bodies tend to stop working if they get too cold or stay still for months. And really, why would we bother? Humans have enjoyed fire and hunted large game for millions of years, so we don’t really need to hibernate, especially in an area as gorgeous as Spain. Right?

“Wrong!” say the researchers, who point out that these humans were living in one of the coldest, driest glacial periods of the last million years. The weather was brutal, there was little evidence of fire use (which didn’t become a regular thing for another fifty thousand years), and there wasn’t enough food to survive the winter. By contrast, other Indigenous peoples living in harsh climates, like the Inuit or Sami, could eat fish, seal, or caribou meat all year, so they never needed to hibernate.

The hibernating fat-tailed dwarf lemur shares 98% of our human genes. Its fat tail provides energy while it’s zonked out.

 

Not all scientists are convinced that the bones prove that humans could hibernate. But some other primates—our evolutionary cousins—sure can. The fat-tailed dwarf lemur for instance, with whom we share 98% of our genes. Why the fat tail? To provide it with energy while it’s zonked out for half the year of course! Whatever genetic basis there is for hibernation, it’s probably lurking somewhere in our genes. Convinced or not, many people are interested, and not just because some of us find winters a little long for our liking. NASA is researching the possibility of having astronauts hibernate for weeks at a time, in order to reduce the food and materials needed on long journeys to deep space.

Medical researchers are working on “inducing hibernation” in patients with severe trauma who are on the brink of bleeding to death. This would allow doctors extra time to examine patients, stop the bleeding, and perform surgery before bringing them back to, well, life.
All of this makes me appreciate how fascinating hibernation really is, was, and could be. But also, I’m now feeling awfully grateful that we don’t need to do it ourselves!

Math, Religion, and Chimpanzees

Photo credit: Aaron Logan

The farmhouse was old. The sixteen foot dining table we were seated at was too. This was a typical gathering with my in-laws, deeply committed Christians. It was during one such dinner that a someone said, "chimps share over 99% of our DNA because they were created by God to test our faith."

By this time, I`d just spent several years of graduate school in the same department as the famed atheist Richard Dawkins. When I passed by his office, I used to stop to read the latest hate mail taped to his door, presumably sent by Christians who believed damning Dawkins to Hell was the best way to help him avoid it. So, while it was a shock at first, I was getting used to the fact that a few of Earth`s modern citizens believe humans walked alongside dinosaurs.

In that Canadian dining room, face-to-face with similarly twisted logic, I realized the root of the "evolution vs. religion debate" is fear. The idea that humans came into being just like all the other beasts lovingly housed on the Ark threatens some Christians` identity in a way that is so terrifying they`ll do mental gymnastics to avoid it, and a few feel pushed to more aggressive defense tactics.

I was glad of this insight when, as a student at teacher`s college, I was charged with teaching evolution to a class of grade 12s in a public high school in a large Ontario city. The experienced science teacher whose class I was borrowing, whose job it was to mentor me, confessed that he'd had a difficult time with the subject, though he'd not succumbed to the temptation of reducing the unit to a brief overview delivered in as little time as possible, as had some of his colleagues. In the photocopying room on the first day, a fellow student teacher exclaimed above the whizzing, flashing 21st century technology, "you`re allowed to teach that?"

This was going to be harder than I thought.

First, I asked the students to indicate if they believed in evolution - anonymously. About half of them indicated so. Then, I taught my heart out, while trying to calm potential fears: I mentioned the polls of scientists, half of whom report belief in a Higher Power; the same stats as the rest of the population. I suggested belief in God is not reliant on science for proof or disproof; indeed it cannot be. I told them about Christians who study evolution, and I compared the issue of evolution in our society to the long since (largely) resolved issue of the Earth being round, not flat.

Three weeks later, I repeated my survey. A little more than half were convinced. From this I concluded:

1. The fear of evolution runs deep;
2. High school is much too late to teach evolution – students have already made up their minds based on only God-knows-what; and,
3. I had failed.

Recently, I’ve decided I might have been complicating the issue. Now, on the rare occasion that anyone asks, "what is evolution?" I say, "evolution is simply math." We have genes. Genes vary, so we`re all different. Any combination of genes that is more likely to survive and reproduce is… (Drum Roll)…more likely to survive and reproduce. I figure it is pretty hard to argue with that, though I`m sure someone will.

Alas, if only our ideas evolved as efficiently as our genes do.