"Dolphins tend to strike a deep emotional chord in many people who encounter them. Famous for their intelligence and physical ability, there have been reports that the marine mammals have come to the rescue of humans at sea.

Writer Susan Casey tells Fresh Air's Dave Davies about an instance in which a scientist who was watching dolphins hunt noticed that they suddenly bolted for deeper water. He followed them and found that the dolphins had formed a circle.

'In the center of the circle there was a young girl floating with a suicide note,' Casey says. 'And she was very close to dead, but she wasn't dead. ... The girl was saved.'  "

Dave Davies interviews author Susan Casey for NPR's Fresh Air August 4, 2015. [2]