James Snyder noticed one day that a frog had climbed onto a tree in his backyard in southern Florida and swallowed one of his Christmas lights. He snapped this eerie photo in which the light glows through the frog’s stomach, like a herpetological holiday ornament.

This frog’s behavior seems weirdly stupid. But there’s actually a wisdom of sorts in swallowing a Christmas light–if you’re a Cuban tree frog, that is. For thousands of years, the only glows your ancestors ever saw on a tree came from luminescent insects. If they responded to a little glow by attacking, they got a meal. They were more likely to survive and have baby frogs. The frogs that didn’t respond? Some of them may have done just fine. But others may have gone hungry. The males might have struggled to attract a mate; the females might have laid small eggs that failed to develop.

Continue reading “Freeing Animals From Our Evolutionary Traps”

Cancer may not seem to have much to do with evolution, but they’re actually intimately linked. Cancer cells evolve within tumors, becoming better at exploiting our bodies and resisting cancer drugs. We have evolved a number of adaptations to fight cancer–or at least to put it off until past our child-bearing years. The intersection of cancer and evolution has become so fruitful that there’s now a biennial international meeting on the subject. This year, the meeting organizers asked me to give a public lecture on cancer and evolution in San Francisco. My talk, “The Devil’s Tumor,” will take place on Friday, June 14, at 7 pm–followed by a performance by the one and only Baba Brinkman. Details here. I hope Bay Area folk can join us!

Originally published June 4, 2013. Copyright 2013 Carl Zimmer.

The New York Times, June 3, 2013

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One day in 1788, students at the Hunterian School of Medicine in London were opening a cadaver when they discovered something startling. The dead man’s anatomy was a mirror image of normal. His liver was on his left side instead of the right. His heart had beaten on his right side, not his left.

The students had never seen anything like it, and they rushed to find their teacher, the Scottish physician Matthew Baillie, who was just as stunned as they were. “It is so extraordinary as scarcely to have been seen by any of the most celebrated anatomists,” he later wrote.

Continue reading “Growing Left, Growing Right”

Not long ago, a friend of mine asked me if I had heard of a condition called situs inversus. He had learned about it when his grandson had been born with his internal organs flipped–heart on the right, liver on the left, and so on. Despite that remarkable reversal, the boy was fine. His story got me curious about how the condition happens–and how our bodies, for the most part, figure out which side is which. The result is a story in tomorrow’s New York Times. Check it out.

Originally published June 3, 2013. Copyright 2013 Carl Zimmer.

The Atlantic, June 2013

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When Jeannie Peeper was born in 1958, there was only one thing amiss: her big toes were short and crooked. Doctors fitted her with toe braces and sent her home. Two months later, a bulbous swelling appeared on the back of Peeper’s head. Her parents didn’t know why: she hadn’t hit her head on the side of her crib; she didn’t have an infected scratch. After a few days, the swelling vanished as quickly as it had arrived.

When Peeper’s mother noticed that the baby couldn’t open her mouth as wide as her sisters and brothers, she took her to the first of various doctors, seeking an explanation for her seemingly random assortment of symptoms. Peeper was 4 when the Mayo Clinic confirmed a diagnosis: she had a disorder known as fibrodysplasia ossificans progressiva (FOP).

Continue reading “The Girl Who Turned to Bone”