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Foster and Kreitzman - Seasons of Life - American wood frog



Type of Spiritual Experience


A description of the experience

Seasons of Life – Russell G Foster and Leon Kreitzman

The American wood frog astounded Captain Francis Smith, who reported on it in his ship’s log near the Canadian Arctic Circle in May 1747. 

With the onset of the shortening days of winter, the wood frog buries itself in the soil, often occupying a burrow made by another animal, and becomes immobile.  As the temperature falls, the frog’s toes begin to freeze.  This triggers the conversion of glycogen stores in the liver to glucose, which enters the blood and from there it travels to all the intracellular and extracellular spaces of the body. 

The glucose acts as antifreeze, lowering the freezing point of water and preventing the formation of ice crystals and the movement of water out of cells.  Apart from safely freezing, the wood frog stops its heart beating and ceases to breathe, but as Captain Smith observed ‘Come Spring, when the land thaws, so does his body.  Within an hour or two the Frog will recover his Summer activity and leap as usual’.

The source of the experience

Foster and Kreitzmann

Concepts, symbols and science items


Science Items

Activities and commonsteps