The hydra is a small, simple creature that lacks a brain, but new research shows that it sleeps. Traditionally, it was assumed that a brain was necessary for sleep. Researchers would study sleep through the use of EEGs among animals with brains. Sleep physiologist Irene Tobler was initially dismissed for suggesting that cockroaches slept, but eventually, it was found that even flies and jellyfish slept. It has been suggested that sleep allows certain biochemical reactions to take place, or that it may divert energy from alertness and movement into other processes. The next step may be to study whether animals without neurons, such as sponges, can sleep.
- The hydra doesn’t have a brain, but studies show it often drops into a sleep-like state.
- Researchers would investigate sleep by studying EEGs, which meant studying animals with brains.
- Sleep may serve to divert energy that would be used by alertness and movement into other processes.
“For more than a century, researchers who study sleep have looked for its purpose and structure in the brain.”