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Biological Miracle – Wood Frog

(www.nps.gov)
501 points thunderbong | 1 comments | 15 Nov 24 18:16 UTC | HN request time: 0.233s | source
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abound ◴[16 Nov 24 04:12 UTC] No.42154107[source]▶
> Nobody yet understands what starts the wood frog’s heart after being frozen and inert for the entire northern winter.

To me, that's the most fascinating part of the (already quite fascinating) story. Frog is frozen solid, there is no (to our knowledge) heartbeat or brain activity. It thaws and something happens that gets it going again.

I have trouble imagining what that mechanism could even look like. Tiny portion of brain responsible for keeping track of frozen-ness? Some chemical signaling from within the body cavity?

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1. sandworm101 ◴[16 Nov 24 11:48 UTC] No.42155919[source]▶
Most likely it isnt that the heart stops or starts in response to freezing. The heartbeat signal probably runs 24/7 unless inhibited by freezing. So as soon as it thaws, the signaling bit resumes its pulsing and the rest of the heart begins to beats as it also thaws. The order in which organs thaw would be regulated by sugar levels. Remember too that at this scale frogs can absorb much of their needed O2 through their skin. A steady heartbeat isn't as essential as it is with us.