Wood frogs (Rana sylvaticus) can survive being frozen for up to 7 months at temperatures as low as -16 °C. Their breathing stops, their heart stops and all signs of life disappear. (Source)

I have looked for research that shows that when these frogs thaw in spring, they retain memories from before they became frozen, but I haven't found any. Can anyone give me any insights?

Note: This research shows how butterflies can remember experiences they had as caterpillars, before their metamorphosis. Perhaps something similar can be done or has been done with wood frogs?

  • $\begingroup$ sweet experiment! good luck. $\endgroup$
    – Willk
    Jan 22 '20 at 23:54

Wood frogs are highly philopatric to their breeding ponds. And the fact that they return to the same pond after multiple winters, would indicate that, at the very least, they must retain at least some spatial memory after freezing.

It is worth noting that a frozen wood frog is not nearly the same scenario as a butterfly metamorphing. Butterfly metamorphosis involves complex reintegration of all bodily systems, whereas frog brains do not reform during the winter--they just cease neurological activity. Even frog metamorphosis is less complex since much of the chondocranium and brain morphology is retained from tadpole to frog.

I know it wasn't the original question, but it is relevant to note that tadpoles seem to retain their personality through metamorphosis (see Wilson & Krause, 2012; Koenig & Ousterhout, 2018), which also seems to indicate that they have neurological stability.


Wilson, A. D. M., & Krause, J. (2012). Personality and metamorphosis: is behavioral variation consistent across ontogenetic niche shifts? Behavioral Ecology: Official Journal of the International Society for Behavioral Ecology, 23(6), 1316–1323.

Koenig, A. M., & Ousterhout, B. H. (2018). Behavioral syndrome persists over metamorphosis in a pond-breeding amphibian. Behavioral Ecology and Sociobiology, 72(12), 184.


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