Animal Behavior Who sleeps for 90% of the day? March 11, 2026 by Mercier | Leave a Comment While no single animal species consistently sleeps for 90% of the day, some animals, particularly newborn mammals and certain marine life, can spend an exceptionally large portion of their lives in a state of rest or dormancy. This prolonged sleep is crucial for their development, survival, and energy conservation. Understanding Prolonged Sleep in the Animal […] Read more ยป