3 ms·
It's weird they don't mention the much more obvious fact that an air-breathing mammal might need to maintain some level of alertness when sleeping in water.
by John_KZ 8y ago
It's weird they don't mention the much more obvious fact that an air-breathing mammal might need to maintain some level of alertness when sleeping in water.
- djmips 8y agoFrom the article: "These marine mammals have evolved a half-brain style of sleeping, perhaps as a way to remain alert enough to avoid predators and drowning."