Will marine mammals like dolphins and whales die if taken out of water? (Quora Repost)

Yes, Marine Mammals will die if taken out of water. Agreed they breathe air but there are other factors too.

1. Their bodies have grown huge as a result of water and most of their skeletons cannot take their body weight as the water ,rather the sea supports their body weight. As a result their internal organs collaps on themselves.
2. Body heat regulation. Though they are warm blooded animals a majority of their thermal regulation is as a result of contact with water. They tend to overheat. PS: you may have seen volunteers helping out beached whales by covering them with coll, wet cloth/blankets
3. Food. They will starve as a result of points 1 and 2.