Invertebrates Sleep
Transparent octopus larvae showing the brain, the white cloudy stuff between its eyes. My science-geek book club just finished reading Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness by Peter Godfrey-Smith. This got me going down the rabbit hole, not of consciousness exactly, but sleep. Since Octopods are wicked smart, the expectation is that their sleep patterns would be akin to those of vertebrates, most of which are kind of smart, while other lowly dumb invertebrates would exhibit different sleep patterns. On the other hand, since sleep is an ancient process, maybe braininess does not influence the pattern. Jellys and flatworms have sleep-like states and lack a centralized nervous system, suggesting that sleep appeared early in the history of animal life. Thus sleep appears to be a fundamental biological function for all animals; well, maybe not sponges. It’s very hard to tell if a sponge is sleeping. We know some reasons...