LiveScience explains why penguins stopped flying:
To learn more about the energy costs that eventually grounded flighted penguin ancestors, researchers looked to penguinlike seabirds in the Northern Hemisphere that still use their wings to dive and to fly. The team studied thick-billed murres in the Canadaian Arctic, outfitting them with location trackers and measuring their energy expenditure with injections of tracer isotopes, which are variations of an element with different numbers of neutrons.
They found that the double life takes its toll. The murre’s flight cost was much higher than expected, the researchers said. In fact, the energy needed for flight was higher than the flight cost of any bird, surpassing the previous record-holder, the bar-headed goose, which makes a demanding migration over the Himalayas.
Compared with birds that propel themselves with their feet to swim, like pelagic cormorants, the murres used less energy when diving. The murres, however, still had higher energy costs for swimming than penguins do, the researchers said.
I have started reading to Lain. Mostly we’re in the habit of trying to read her to bed. Which is a bit difficult, since she is at the point where she is as interested in eating the book as she is in listening to me read from it. I’ve had to sideline attempts to use the Android tablet to read ebooks to her because “Look, brighty bright! Must touch the brighty bright! Must put the brighty bright in my mouth!” and I get only a few minutes before she is more frustrated that I am keeping the brighty bright away from her than she is soothed or made happy by my speaking.
Anyhow, one of the books that I read is about wings. Wings on birds, planes, and so on. There is a part where it says something to the effect of “wings are there to make things fly” and on that page, it shows a penguin. So every time I read her the book, I feel the need to correct it “Wings are there to make things fly – unless you’re a penguin.” It mentions the wings on a chair later, and I also mark that as an exception to the “wings are there to make things fly” rule.
Eventually we’ll start talking about the aerodynamics of the wings on the angel and how it is unlikely those wings are sufficient to allow the angel to fly. But that can wait until she’s older.