First, this Note on Emerging Science from Maggie Villiger.

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VILLIGER: Regurgitated food might not sound like an appetizing meal, but that's what king penguins feed their babies. Consider that the food these penguin kids are getting may have originally been eaten up to three weeks ago, and mealtime starts to sound even less appealing.

But king penguins have a unique ability to keep undigested food fresh in their stomachs for weeks on end while they fast. And recently, researchers have been looking into just how the birds prevent food stored in their stomachs from going bad. They visited king penguin colonies in Antarctica where some males were fasting while incubating their eggs. The scientists took samples of the birds' stomach contents.

They found that even though conditions like the temperature, pH and nutrients available inside the stomach were all favorable for bacterial growth, bacteria were not flourishing. In fact, dead or deformed bacteria and spores were much more common in the stomachs of penguins that were conserving food than they were in penguins that were digesting their meals.

Scientists think penguin bellies contain an anti-microbial substance that helps keep food from spoiling. They hope to further test the birds' stomach contents to identify the anti-microbial substance and figure out how the penguins control these bacteria inhibitors.

That's this week's Note on Emerging Science. I'm Maggie Villiger.

CURWOOD: And you're listening to Living on Earth.

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