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Common Gartersnakes Brumating

1-28-19 gartersnake img_4888Somewhere between two and four feet (depending on where you live in New England) beneath our feet there is a “frost line” below which the ground water in soil doesn’t freeze. Snakes, being reptiles, are ectotherms, and their bodies assume the temperature of the air around them. In order to avoid being frozen to death in the winter, they retreat below the frost line, where they enter a state called brumation – the cold-blooded term for a state of torpor and inactivity that is not true hibernation, but in which a dramatic slowing down of bodily functions occurs. Crevices in south-facing rocky ledges and abandoned woodchuck, fox and skunk dens (and human cellars) often serve as hibernacula, or winter shelters. Common Gartersnakes are known to gather in large numbers (one Canadian den served as a hibernaculum for 8,000 gartersnakes), in order to concentrate the small amount of heat their bodies produce in the winter.

As the air temperature lowers in the fall, a snake’s body temperature falls and its metabolism decreases dramatically. Gartersnakes actively prepare for this by not eating for several weeks prior to hibernating. This allows all of the food they previously consumed to be completely broken down and absorbed into their system. To enhance this process, gartersnakes bask in the sun both before and during their early days of sheltering in hibernacula, warming themselves so as to increase the rate of their metabolism just prior to hibernating.

Should a snake happen to eat a large grasshopper, earthworm or small frog just prior to entering brumation, the snake may become extremely lethargic due to the slowing down of its metabolism, and the contents of its stomach may not be digested as quickly. The longer it takes to process food in its stomach, the greater the chances that this dead material will start to decay, which could result in serious illness to the snake.

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13 responses

  1. nangalland

    Hi Mary – stories like this increase my amazement at the wisdom of Mother Nature. If only we humans would learn to trust that as well as the rest of the occupants of this earth!! love, Nan


    January 28, 2019 at 8:12 am

  2. Alice Pratt

    I’m always happy to see snakes, in our yard…Gartersnakes…especially young ones and Eastern ring neck snakes.

    January 28, 2019 at 8:35 am

  3. Diane Alexander

    Wish I could hibernate in a hole like this. 🙂

    January 28, 2019 at 8:43 am

  4. Ruth Gross

    Mary, Thank you for your post- fascinating, I read it twice!

    Sent from my iPad


    January 28, 2019 at 9:34 am

  5. Stein

    So interesting about their eating habits!

    January 28, 2019 at 9:52 am

  6. Kathie Fiveash

    If there is a hibernaculum nearby, would we expect to see snakes out basking on warm(ish) early winter days?

    January 28, 2019 at 10:02 am

    • Hi Kathie,
      No, typically you might see them in late fall, basking near their hibernaculum, but it would be pretty unusual to see one after freezing temperatures are steady.

      January 28, 2019 at 10:53 am

  7. Alan Keitt

    hi Mary,

    Cold here in Florida and the gators are laying low.

    I recently came across the Wahington Post contest some years back about changing/adding or subtracting one letter of word so as to jiggle it’s meaning. I cheated and added two letters.

    BRUMINATION. – the boring mental activity of a Garter snake spending the winter below the frost line.

    Sorry, couldn’t resist

    Alan Keitt

    January 28, 2019 at 11:20 am

    • Alan, you are brilliant!!! So good to hear from you. My very best to you and Ruth.

      January 28, 2019 at 12:06 pm

  8. Very “cool” info!

    January 28, 2019 at 11:55 am

  9. Tamson

    I don’t know where our local garter snakes bruminate, but I have two large milk snakes in the crawl space under my house. I always know when they’re down for the winter because the mice come out to play in large numbers.

    January 28, 2019 at 1:30 pm

  10. Fascinating!

    January 29, 2019 at 8:03 pm

  11. Peggy

    Fascinating! Thank you.

    January 30, 2019 at 9:01 am

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