Egg Shape Mystery

How do you like your eggs – over easy? Sunny-side up? Pointy??!

This is Sandra Tsing Loh with the Loh Down on Science.

Some birds lay eggs shaped like teardrops. Others look like a ball. And there’s everything in between! Why so MANY different shapes?

Enter Mary Caswell Stoddard, a biologist at Princeton University. She led an international team to CRACK this quandary.

Their computer program sorted fifty thousand egg photos based on two criteria. Pointiness and elongation. For example, some eggs are spherical. Neither pointy nor elongated. Others are shaped like an avocado! What gives?

The data point to the sky. Turns out, egg shape is related to a bird’s flight ability! Strong fliers lay eggs that are either more elongated or more pointy.

Stoddard thinks this is related to the streamlined body required for strong flight. Powerful flyers have narrower pelvises than their less athletic cousins. Compared to a sphere of equal girth, an elongated or pointy egg contains more volume. That means more nutrients for the yet-to-hatch baby bird!

EGG-cellent conclusion! Those researchers must really be flying high!