Despite being mollusks, octopuses have a complex genome that is nearly the size of the human genome.
Sorry BUGS, your brain isn't equipped for REM sleep, or any sleep for that matter.
How did some animals manage to survive the extinction?
It would only take a single oversized meal to kill or cause brain injury to a squid.
For penguins, laying eggs can be one dangerous job. Learn more on this Moment of Science.
Almost all mammals, in fact, have REM sleep; birds do too, although only in the early parts of their lives. It seems that sleep and REM are required by a particularly complex kind of brain.