When birds sit quietly on a branch for long periods during winter, they are not usually sleeping but conserving energy, ...

A few weeks ago when I was out cycling with some friends, we saw a few birds who looked like they were sleeping. Someone asked me what they were doing, and I said they were resting or sleeping but I'd ...

Birds exist in a fluid and unpredictable world. Survival depends on remaining constantly alert, adapting and responding to encounters with predators and environmental conditions that change with the ...

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.

Sleep looks peaceful on the outside, but inside the brain, it is anything but ...

Researchers have tracked muscle contractions in a bird's vocal tract, and reconstructed the song it was silently singing in its sleep. The resulting audio is a very specific call, allowing the team to ...