Freeze Avoidance in Overwintering Blanding’s Turtles (Emydoidea blandingii)
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| Freeze Avoidance and Freeze Tolerance: An Overview | Hatchling Blanding’s turtles (Emydoidea blandingii) exhibit overwintering strategies that are largely dependent on behavior (Packard et al., 1999). Hatchlings typically do not overwinter in natal nests following hatching, likely because of constraints on their capacity for freeze tolerance (Packard et al., 2000). In ice-free conditions, hatchling Blanding’s turtles are able to survive cooling to -6 degrees Celsius before experiencing spontaneous freezing of body fluid (Packard et al., 2000). However, in conditions that subject hatchlings to ice exposure in frozen soil, freezing of body fluid occurs near the equilibrium freezing point (-0.7 degrees Celsius) and freezing below -2.5 degrees Celsius is fatal, suggesting that emergence from natal nests before winter is an adaptive freeze avoidance strategy to prevent fatal freezing (Packard et al., 2000). |
| Supercooling | |
| Freeze Avoidance in Overwintering Snapping Turtle (Chelydra serpentina) Hatchlings | |
| Variation in Freeze Tolerance Between Species | Table 1. Adapted from Packard et al., 2000. |
| Freeze Tolerance in Overwintering Slider (Trachemys scripta) Hatchlings | |
| Freeze Tolerance in Overwintering Northern Map Turtle (Graptemys geographica) Hatchlings | |
| Literature Cited | |
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