https://apnews.com/projects/extreme-animal-sleep/
"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 risky," said Paul-Antoine Libourel, a researcher at the Neuroscience Research Center of Lyon in France.
When animals nod off, they're most vulnerable to sneaky predators
