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Freeze Avoidance and Freeze Tolerance: An Overview

   
Supercooling Freeze Avoidance
   
Freeze Avoidance in Overwintering Snapping Turtle (Chelydra serpentina) Hatchlings Freeze avoidance as a strategy for coping with exposure to temperatures lower than the freezing point of body fluids in animals is based on preventing the freezing of body fluids, keeping body fluids in a liquid state (Storey and Storey, 1996).
Freeze Avoidance in Overwintering Blanding’s Turtles (Emydoidea blandingii)

Variation in Freeze Tolerance Between Species  
 

Photo by Christian Oldham

Freeze Tolerance in Overwintering Slider (Trachemys scripta) Hatchlings Freeze Tolerance
   
Freeze Tolerance in Overwintering Northern Map Turtle (Graptemys geographica) Hatchlings Freeze tolerance as an overwintering strategy of vertebrates is facilitated by biophysical and physiological responses to ice formation within body tissue (Costanzo and Lee, 1994). During the process of freezing, body tissues are subjected to cell dehydration and cell membrane damage, damage to vessels, and buildup of lactate and alanine in conjunction with a loss of ATP (Costanzo and Lee, 1996). Damage to organisms as a result of freezing and thawing can be mitigated through the use of cryoprotectant chemicals, such as glucose in the wood frog (Rana sylvatica), or gradual ice crystallization within tissues (Costanzo and Lee, 1994).
   
Literature Cited  
   
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