Was out on a boat this summer, on a hot day with moist air. Normally (in summer) it's cooler out on the water. But on that day I had a kind of 'choking' feelin

Was out on a boat this summer, on a hot day with moist air. Normally (in summer) it's cooler out on the water. But on that day I had a kind of 'choking' feeling even on the middle of a lake. Like being in an elevator or bus packed with people & not enough ventilation. It was easy enough to take a swim to cool down. But for these dolphins? The water not cooling them down. Swimming at all would raise their body temperature. Out in the ocean they could have dived to deeper (cooler) waters. Or swim to cooler areas. But in the lake/river they were in? No escape from the hot water. One can only imagine how desperate they must have felt right before they died.