Saturday, June 22, 2013

Wood Frog

Wood Frog - Rana sylvatica

While trying to bushwhack around a flooded area, I saw a movement on the ground. The creature "disappeared" and I presumed was gone. However, to be sure, I paused, bent over, and looked carefully. The Wood Frog was the identical color of the mud and the wood.

The humidity was very high. The sun was above the forest canopy, the air was thick and warm, and the surface of every branch and leaf was wet to touch. Very tropical for Calgary. My glasses kept steaming up as I tried to take photographs. After each photograph, I wiped my glasses and each time the frog "disappeared." The camouflage coloration of this frog was so good that if I had not known where to look, then the frog would have been truly invisible. Amazing.

The Wood Frog hibernates by "freezing solid." There is no heartbeat, no respiration, and no neural activity. Once the temperature reaches minus 2 degrees C, the Wood Frog liver pumps out glucose and this carbohydrate is transported into cells in very high concentrations, and water follows such that the cells swell. This apparently prevents cell death. In the spring, the Wood Frog thaws out and hops away. 

Gadd, Ben. Handbook of the Canadian Rockies. Corax Press. Jasper, Alberta. 1986.

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