4 December 2023

Lots of animals don’t sleep for long periods like we do but a new study has found a polar opposite in Antarctica (pun intended) where chinstrap penguins (Pygoscelis antarcticus) take 10,000 4-second naps each day during the breeding season. In this way they accrue 11 hours of daily sleep.

For us, the micronaps would be a form of sleep torture since we cannot enter restorative deep sleep in such a short time. But the chinstrap penguins do.

Researchers led by Won Young Lee, a behavioral ecologist at the Korea Polar Research Institute, captured 14 penguins at the King Georges Island breeding colony and fitted them with data loggers to measure brain activity and accelerometers to record muscle movements and body positions. They also set up cameras to watch for closing eyes and drooping heads.

Brain waves showed the penguins experience slow wave (deep) sleep during those micro-naps. They nap while incubating or guarding their chicks and even while floating on the ocean.

So now I’m looking at group photos of chinstrap penguins and, sure enough, in every photo some of the adults are sleeping. They’re getting their beauty rest 4 seconds at a time.

Read more in Science Magazine: This Antarctic penguin sleeps 11 hours a day—a few seconds at a time.

26 November 2023

We humans recognize each other by face and can sometimes recognize individuals in other species as well. For instance, African penguins (Spheniscus demersus) have unique patterns of dots on their chests that zookeepers use to tell them apart. Psychologist Luigi Baciadonna wondered if the dots functioned the same way for the penguins themselves so he ran an experiment at Zoomarine Italia in Rome.

In the experiment individual penguins were herded into a small corral with life-size portraits of two group members, at least one of which was his/her mate. African penguins like to hang out near their mates so if the visiting bird stared at the mate’s portrait and gravitated toward it, he/she was recognizing the mate. The experiment had three variations:

Test #1: Accurate photos: one of the mate, one of another member of the colony. Result: In this video of Test#1 a male penguin, Gerry, is presented with an image of his partner, Fiorella, on the left and one of group member Chicco on the right. Notice what he does.

Test 2: Two photos of the mate: one accurate, one with dots digitally removed. Result: The birds spent more time looking at the mate photo with dots.

Test 3: Dots digitally removed from both photos: mate and another member of the group. Result: The birds no longer seemed to recognize their mate. There was no difference in how long they gazed at the mysteriously spotless portraits.

Quiz! Now that I know African penguins have unique chest dots I discovered that the penguin pictured below is also in a photo above. Which one is he?

Visit the National Aviary in Pittsburgh to check out the African penguins’ dotted chests at Penguin Point.

Read more about the study at Science Direct: African penguins utilize their ventral dot patterns for individual recognition

(credits are in the captions)