Do Dophins sleep with 1 eye open and if so why???????

Question: Do Dophins sleep with 1 eye open and if so why???????
- Keywords:
  dophin,
  sleep
Asked by luvinscience1202 to Ed, Hayley, Jason, Sophie on 20 Mar 2013.
- Sophie Holles answered on 20 Mar 2013:
  
  Yes they do! Because they have what’s called ‘unihemispheric sleep’ where only one half of their brain is sleeping at a time. This keeps them safe from shark attacks and means they won’t drown because they have to go to the surface to breathe.

Question: Do Dophins sleep with 1 eye open and if so why???????