lethargy

For six to eight months each year, striped ground squirrels do not leave their small underground burrows and do not need to eat or drink at all.

Contrary to the usual default, the record of natural sleep time is not a lazy species.

This finding may help to develop new treatments for patients with sleep disorders, or at least help to better understand what makes them unable to get a good night's sleep.

American pop queen Britney Spears is one of the many victims of psychological disorder called 'personality in the abyss'.