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 ...

Every animal with a brain needs sleep — and even a few without a brain do, too. Humans sleep, birds sleep, whales sleep and even jellyfish sleep. Sleep is universal “even though it’s actually very ...

Moving‍‌‍‍‌‍‌‍‍‌ long distances through migration is a hard task that often pushes the animals' physiological limits. However, the case of birds that can sleep while flying is probably the most ...

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.

When birds sit quietly on a branch for long periods during winter, they aren’t usually sleeping, but rather conserving energy. When food is scarce, active foraging can waste valuable energy, so ...