The impossible claim

This frog freezes solid every winter — no breathing, no heartbeat, up to 70% of its body turned to ice — then thaws back to life in spring.

The verified facts

The wood frog (Lithobates sylvaticus) survives Alaskan winters by letting itself freeze. Its liver floods its blood with glucose and urea — natural cryoprotectants that protect cells while ice fills the spaces between them. Its heart stops, brain activity flatlines, and up to ~70% of body water turns to ice for up to seven months.

  • In spring, the heart restarts on its own within hours of thawing
  • It can tolerate the freezing/thawing cycle repeatedly across winters
  • It freezes on purpose — choosing winter shelter where ice will form first

Watch

🎬 See the Short on YouTube — The Wood Frog That Freezes Solid

Sources

  • Storey, K. B. & Storey, J. M. (1986). Freeze tolerance in the wood frog. Journal of Comparative Physiology B.
  • Costanzo, J. P. et al. (2013). Hibernation physiology, freezing adaptation in Alaskan wood frogs. Journal of Experimental Biology.
  • Larson, D. J. et al. (2014). Wood frog adaptation to subarctic cold. Journal of Experimental Biology.

Part of Impossible Creatures — every fact verified, every creature real. Watch the Shorts at https://www.youtube.com/@taginbertcom.