This is scientific American 60 second science. I'm Christopher Intagiyata.

In January 2014, an epic cold wave swept across the southeast, a snowpoculips so severe that thousands of drivers in Atlanta

abandoned their cars on icy highways and interstates.

And I'm from the south. I was raised in South Carolina and I can tell you that in the South we do not do cold at all.

Shane Campbell Staten was watching it all unfold from Harvard where he was getting his

PhD. He just wrapped up his last field season in Texas, studying the Green Anole Lizard, and as he was scanning through photos of the storm, he came across something unexpected, a photo that included his research subject.

There is this one picture of a green and old that was upside down,

dead in the snow, and it was sort of a eureka moment.

And I thought to myself, well, maybe I should go back out

and see if these populations that I'd just been studying if they had showed any sort of response to this pretty extreme weather event in the south.

And so that's what he did because here's the bit of

serendipity. He'd actually been studying the cold tolerance of different

populations of these lizards and now the cold snap had just delivered the

perfect experiment, a chance to see natural selection in action.

So I went back in April right after these winter storms had subsided, and I noticed that in the

south, like the southernmost population, the survivors of the storm were able to maintain function

at significantly colder temperatures than the population before the storm.

And this ability to maintain function at colder temperatures

is something that we typically see much farther north. He did genetic analyses

too and he found that the genes switched on in the surviving southern lizards overlapped with genes more typically

turned on in their cold-hardy northern cousins.

And the survivors also carried variations in their DNA that more closely matched northern lizards.

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