Human babies scream when their meal is a few minutes late, but baby penguins are better at keeping their cool—literally. As almost perfectly round balls of fluff, king penguin chicks are well-adapted to their cold climate, but when their parents leave to go forage, the babies are left alone without food for up to 5 months at a time. To study how chicks conserve their energy during this period, researchers surgically implanted data-loggers into 10 king penguins between 3 to 4 months of age, monitoring the temperature in their stomachs, chest cavity, and fat over a period of about 7 months. The chicks' internal body temperature dropped by up to 15˚C while fasting in cold or rainy weather, the researchers report online today in Nature Communications. That's a surprisingly large dip for such a big baby bird (10 kilograms); the Australian tawny frogmouth, the biggest bird previously found to drop its body temperature in response to winter weather, weighs only 500 grams. The temperature of penguin chicks even seems to drop when they eat a chilly meal: When their parents come back and give them a mouthful of cold, already-been-chewed fish, the chick's body temp plummets 15˚C.
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