False colour electron microscope images of some of the 300 species (types) of bacteria found in your MOUTH!

Unihemispheric slow-wave sleep

“The common swift (as well as some other birds and some aquatic animals) is capable of unihemispheric slow-wave sleep: one half of the brain is asleep while the other half remains alert (including an open eye). This makes long, non-stop migrations possible.”