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Wood Frogs & Spring Peepers On The Move

3-29-16 road frogs 015Although the temperature hovered around 32°F.  last night in central Vermont, wood frogs and spring peepers were on the move.  Usually it is above 40° or 45° before you see the earliest of our breeding amphibians, but a few hardy souls ventured forth to their breeding pools and ponds under cover of darkness and  rain yesterday.  Those that breed in vernal pools are in a hurry to take advantage of every day, as the eggs they lay must complete metamorphosis by the time their pool dries up, often in mid- to late summer.

Both of these species of frogs are freeze tolerant.  Wood frogs are coming out of a state in which they haven’t taken a breath and their heart hasn’t beaten for several months.  Prior to hibernation they convert glycogen in their bodies into glucose, a form of antifreeze that helps prevent the water within their cells from freezing, which would kill them.  However, the water outside their cells does freeze.  Amazingly, wood frogs can survive having up to 65% of this water frozen, yet when warm weather arrives, they thaw and move about in a matter of hours.

If you rescue these woodland amphibians that are crossing roads (where so many of them get run over at night) during their migration to their breeding pools, take note of the temperature of their body.  Often they are still quite cold to the touch — colder than the air, even – which fortunately makes it difficult for them to move fast enough to escape your helping hands. (Photo: Amorous wood frogs getting a head start as they cross a road to get to breeding pool.)

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10 responses

  1. Alice Pratt

    Mary….I really smiled at the term “amorous woodfrogs” 😍 …it’s very descriptive. Peepers are so enjoyable to listen to.

    March 29, 2016 at 7:03 am

  2. Penny

    Did the male help the hopping at all? or just ride along and let the lady do the work?

    March 29, 2016 at 7:36 am

    • What do you think??? Of course she did all the work!

      March 29, 2016 at 10:22 am

  3. Do they change glycogen to glucose or glucose to glycogen. I thought glycogen was the antifreeze, but then I may be mistaken, but that would be a first ; ).

    March 29, 2016 at 8:58 am

  4. Pingback: Hopping Down the Wood Frog Trail | A Moveable Garden

  5. Alison Sanders-Fleming

    hi mary, i thought it was “big night” in lincoln some weeks ago, a rainy friday when various little creatures were crossing lincoln road between trapelo and route 2, were we so far ahead of vermont? ask (friend of terri morgan’s) >

    March 30, 2016 at 3:43 am

    • Yes, you were! Frogs and salamanders first started moving last week in Vermont in the Champlain Valley, where they typically are seen first. We still haven’t experienced a full-fledged big night in all parts of Vermont, but probably will this week.

      March 30, 2016 at 6:17 am

  6. LG

    I have a small pond in Putney, and the wood frogs convened earlier than ever this year (and I discovered only one female victim of the strong squeeze). Then, about 10 days later (for 3 or 4 days just last week) a second gathering occurred, which has not happened in my 10 years of noting the “first quacking of wood frogs.” But the peepers have not started their calls yet (the time lapse between wood frogs and peepers has varied considerably over the years).

    April 4, 2016 at 11:55 am

    • I think the weather is affecting all manner of creatures this year!

      April 4, 2016 at 6:30 pm

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