Birds resting on a beach or a wire often look calm, almost detached from what is happening around them. But that stillness can be misleading. For many species, sleep is not a full shutdown. One eye ...

Forbes contributors publish independent expert analyses and insights. I write about biodiversity and the hidden quirks of the natural world. Frigatebirds can remain airborne for days at a time without ...

Humans do very little when we sleep. This might not seem like a big deal, until you look to the dolphins as they sleep and swim with the pod. Or fur seals, who can sleep while watching out for sharks.

This is read by an automated voice. Please report any issues or inconsistencies here. Animals such as penguins and frigatebirds have evolved extreme sleep strategies — naps that last a few seconds, ...