Biological Miracle – Wood Frog

> 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?

my poor knowledge of biology says it's a deeply unsatisfying "heart beats when enough of the body has thawed for it to beat."

If the heart depends on the brain at all in frogs.

It doesn't, even in humans. There is an independent circuit of special muscle cells right on it that keeps it beating.

So starting and stopping the heart in a controlled manner is pretty interesting, because it has to be well-timed, and there are few obvious and reliable inputs to control it, especially when thawing.

Why doesn't my heart keep beating if my brain dies then? Or would it?

Probably because the brain controls breathing and so the oxygen runs out quickly