When you think of sleeping, you probably don’t picture yourself hanging from a tree branch, floating in the ocean, or ...

While horses do lie down for deeper REM sleep, who need to lie down to achieve rapid eye movement that is necessary for rest and recovery, they often nap on their feet to stay alert to predators.

Photo from Kenrick Baksh via Unsplash On an island of Trinidad and Tobago, a 5-foot-long predator moved through ... At night, they sleep in the trees. A Chironius nigelnoriegai, or Trinidadian ...

Common thresher sharks are “aggressive predators” that live up to 50 years and can reach lengths of 20 feet, according to National Oceanic and Atmospheric Administration Fisheries. However ...