Sleep Phylogeny: Have We Jumped the Shark?

Sleep is considered to be ubiquitous in the animal kingdom. Scientists in part believe this because sleep is increasingly defined solely by behavioral measures. This has resulted in an astonishing expansion of species reported to sleep. But have we gone too far? Have scientists jumped the shark? This idiom refers to when an idea has exhausted its core intent and creates ideas that are discordant with its original purpose. In this commentary, I discuss what I see as an emerging problem in how we define sleep and the attendant implications.