The Penguin's Solitary Egg.
Reading edition
The female penguin of Patagonia does not commit her offspring to any kind of nest. She constantly carries her solitary egg in a pouch formed by a fold in the skin of the abdomen, and it is held so fast in this that she leaps or sometimes rolls from rock to rock without letting it fall. It is well for her she does so, for should such a mishap befall her the male bird chastises her without pity.