Long Winter’s Nap

Sleep is gaining new respect among human health researchers. They’ve observed correlations between 6-7 hours of quality shut-eye and longevity, improved mood and memory, as well as restoration of immune, nervous, skeletal, and muscular systems.

But getting enough sleep is a challenge in the modern era of artificial lighting and smart devices that PING!  their demands for attention at all hours. Research strongly suggests that a 20 minute catnap, as a supplement to deep (aka slow-wave) sleep, can reduce fatigue, reverse information overload, diminish jet lag, and may even lower coronary (heart disease) mortality.  As such, naps have been gaining in popularity since the benefits were studied and formally reported in the late 1990s.  A little mid-day shut-eye is the 2021 self-care equivalent of drinking 8 glasses of water per day in the ’70s, or walking 10k steps per day in the ’00s.

Compared to Marmota monax (aka groundhog, woodchuck, whistlepig, etc.), though, Homo sapiens are johnnies-come-lately to the concept of a power nap. As a member of the elite group of true hibernators, I’m pretty sure these large** ground squirrels would consider their primate neighbors to be rank amateurs when it comes to snoozing.

groundhog emerging from den by Gilles Gonthier, ccl-by-2.0

Groundhogs and other marmots are obligate hibernators, which means when their annual bedtime arrives they yawn and head for their burrows to snuggle into layers of leafy blankets. It doesn’t matter if Jack Frost has hit town or not, whether Mother Nature has already shut down her buffet, or another season of whatever they’ve been binge-watching on Netflix has just been released.  The calendar says it’s time to turn in, so they do.  By contrast, facultative hibernators respond to cold temperatures, lack of food, or both, rather than to more subtle cues, such as shorter daylight hours.  Mr. Sandman comes like clockwork, and he doesn’t gently sprinkle these creatures with slumber dust; he delivers drowsy dunes of the stuff, causing Groundhogs to sink into a deep slumber. 

Well… that’s not technically true. While it’s fun to reference a famous holiday poem about a visit from Santa for a December blog post, hibernation and sleep are not the same thing at all.  Mammalian hibernators, including Groundhogs, enter a physiological state marked by a a precipitous drop in both heart and respiration rates and a decrease in body temperature close to the ambient temperature inside their below-the-frost-line dens.

Research into this behavior, characterized by periods of both torpor and arousal, has lead to a hypothesis that hibernation actually creates a “sleep debt” that requires the animals to warm up from time to time and actually sleep, despite the increase metabolic demand waking takes on stored fat reserves.

Speaking of the caloric demands on power nappers…. Groundhogs aren’t dilettantes when it comes to the fine art of carbo-loading, either.  Remember, Groundhogs are out for the count during this time so they don’t turn their burrows into pantries and snack their way from autumnal to vernal equinoxes. Typically, they’ll lose half their pre-hiberation weight before emerging in spring so they brace for winter by bulking up. 

When you’re an herbivore who vegetates from three to seven months of the year (depending on the latitude of their home range), provisioning your metabolism for down time requires more than occasionally treating yourself to an entire pint of Ben & Jerry’s when the days get short. No, we’re talking serious hyperphagia (i.e., rapid intake of excessive amounts of food).

Groundhogs achieve maximum mass before their great seasonal retreat by consuming more than a pound a day of wild grasses, dandelion, coltsfoot, buttercup, berries, clover, wild lettuces, and sheep sorrel, along with agricultural and garden crops when they’re available. Groundhogs will also consume miscellaneous small creatures such as insects and snails, but while other members of the Sciuridae clan are definitely omnivores, Groundhogs could be more accurately thought of as opportunivores. Their conspicuous consumption efforts are aided by a metabolism that slows significantly in early summer, allowing Groundhogs to pack on the pounds by producing fat deposits that will fuel their perennial intermission.

This cycle of weight gain and weight loss may sounds familiar although you probably know it by another name: yoyo dieting, a term that references the up-down motion of that venerable spool-and-string toy. The jury is still out on whether bouncing around the dial of a scale has any long-term negative consequences for human health but it’s a life-saver for Groundhogs and other creatures who can’t migrate toward the equator or turn on the furnace when Old Man Winter comes to call.  

As we enter a new year and set ambitious dieting goals that will be hard to sustain past February 2nd, I’d like to suggest a new approach. Because here’s the thing… research has demonstrated a correlation between lack of sleep and weight gain, while other studies have shown that diets don’t work for most people.  So instead of tracking calories to trim down, why not choose a marmot as your wellness role model and resolve to log more sack time?  Want to be more energetic, smarter, healthier, and happier in 2022?  The Groundhog Plan is all that and a bag of chips, a second helping of mashed potatoes, and a slice of pumpkin pie!

** Adult Groundhogs measure an average of 16 to 27 in (42 to 69 cm), nose to tail, and weigh in at anywhere from 4 to 14 lbs (2 to 6 kg), depending on age.


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© 2021 Next-Door Nature— no reprints without written permission from the author. Thanks to the following photographers for making their work available for use through Creative Commons License: Rachid H, Gilles Gonthier, Andy Reago & Chrissy McClarren, Jacque Pinette, and James.

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