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Feeling Froggy?

Short answer: The wood frog (Lithobates sylvaticus), found across North America from the American Midwest and southern Canada to Interior Alaska, can survive with about 65-70% of its body water frozen. While frozen it shows no heartbeat, breathing or circulation.

It builds up urea before winter and floods its tissues with glucose from the liver when ice starts to form; both act as cryoprotectants that limit ice formation and cell shrinkage. When temperatures rise in spring, the frog thaws, its heart starts beating again, and normal functions resume. The footage, credited to Nat Geo Animals, shows wood frogs in water and a close-up of a frog's eye.

VideoWrite-up1 sources

In collections:Extreme Cold

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What should you know about Feeling Froggy??

Quick facts. Each one stands alone and has a stable ID you can cite.

  1. Lithobates sylvaticus.

    DD-758-F01 · Write-up · Exhibit A (Species)

  2. North America, to Interior Alaska.

    DD-758-F02 · Write-up · Exhibit B (Range)

Video transcript: Feeling Froggy?: Wood Frogs Can Freeze Solid in Winter and Thaw Back to Life

Did you know? Wood frogs can survive being frozen solid during winter, with their hearts stopping and as much as 65% of their body water turning to ice. Found across North America, these amphibians survive temperatures that would kill most other vertebrates by flooding their tissues with glucose and urea, which act as natural cytoprotectants. When spring arrives and temperatures rise, the ice melts, their hearts start beating again, and normal bodily functions resume. NOW YOU KNOW!

Burned-in captions, read frame by frame (see transcript.md) · 24.3s Reel ·

Video coming soonFeeling Froggy? · Instagram Reel
Feeling Froggy?: Wood Frogs Can Freeze Solid in Winter and Thaw Back to Life Instagram Reel · · 24.3s

The write-up

Wood frogs can freeze solid in winter and thaw back to life. Their hearts stop until spring.

  1. Exhibit A

    Species

    Lithobates sylvaticus.

  2. Exhibit B

    Range

    North America, to Interior Alaska.

  3. Exhibit C

    Frozen water

    Up to about 65-70%.

  4. Exhibit D

    Vital signs

    None while frozen.

  5. Exhibit E

    Protectants

    Glucose and urea.

Questions people ask about Feeling Froggy?

How much body water can freeze?

Up to 65-70%.

Source: Write-up · Exhibit A (Species) · Wikipedia: Wood frog

Heart while frozen?

No heartbeat.

Source: Write-up · Exhibit B (Range) · Wikipedia: Wood frog

Protective compounds?

Cryoprotectants.

Source: Write-up · Exhibit C (Frozen water) · Wikipedia: Wood frog

Where found?

Wide range.

Source: Write-up · Exhibit D (Vital signs) · Wikipedia: Wood frog

When do they thaw?

Warming.

Source: Write-up · Exhibit E (Protectants) · Wikipedia: Wood frog

Test Your Knowledge

All quizzes →

5 questions, all from this case file. Answers are revealed instantly.

  1. How much body water can freeze?

    1. About 65%
    2. 5%
    3. 100%
    4. 20%
    Show the answer

    Answer: A. About 65% Up to 65-70%. Source: Write-up · Exhibit A (Species) · Wikipedia: Wood frog

  2. Heart while frozen?

    1. Stops
    2. Speeds up
    3. Unchanged
    4. Doubles
    Show the answer

    Answer: A. Stops No heartbeat. Source: Write-up · Exhibit B (Range) · Wikipedia: Wood frog

  3. Protective compounds?

    1. Glucose and urea
    2. Salt and iron
    3. Fat only
    4. Venom
    Show the answer

    Answer: A. Glucose and urea Cryoprotectants. Source: Write-up · Exhibit C (Frozen water) · Wikipedia: Wood frog

  4. Where found?

    1. North America
    2. Australia
    3. Antarctica
    4. Sahara
    Show the answer

    Answer: A. North America Wide range. Source: Write-up · Exhibit D (Vital signs) · Wikipedia: Wood frog

  5. When do they thaw?

    1. Spring
    2. Midwinter
    3. Never
    4. Every night
    Show the answer

    Answer: A. Spring Warming. Source: Write-up · Exhibit E (Protectants) · Wikipedia: Wood frog

Cite this case file

Easterling, Marcus. "Feeling Froggy?." The Detail Department (DetailEnjoyer), case file DD-758, last updated Oct 25, 2026. https://detailenjoyer.com/case/feeling-froggy/

Permalink: https://detailenjoyer.com/case/feeling-froggy/ · Last updated

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