27 January 2009

Searching for snails on a cold day

Back in November when we had our the day after Thanksgiving field trip in the Hoyles Mill Conservation Park, I flagged the locations of 5 dormant and buried Anguispira fergusoni. Yesterday, I went back to check on them.

It was a cold day; the temperature was hovering around freezing. All the small creeks running thru the park were frozen over.


Luckily I had a stable GPS signal and the coordinates measured in November also turned out to be quite accurate and so I didn't have any trouble locating the dead tree where the snails were. All of my 5 little yellow flags marking the exact locations of the buried snails were still standing.


However, I hadn't taken into account one possible complicating factor, that the soil would be frozen. It indeed was and although I could have dug into it—the snails were not very deep—I decided not to do anything forceful lest I broke the snails' shells during the operation.

According to Riddle (1981), Anguispira alternata avoids freezing of its tissues by undergoing supercooling almost down to -16 °C. Hopefully, my snails are doing the same where I left them in November. I will go back there during a warmer period.

Otherwise, it was a good trip that netted a deer skull.

Final post of this series is here.

Riddle, W.A. 1981. Cold hardiness in the woodland snail, Anguispira alternata (Say) (Endodontidae). Journal of Thermal Biology 6:117-120.

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