Dolphins are some of the most intelligent, socially complex animals out there. So it make sense that they would be the ones to star in a thrilling rescue story.

In an excerpt from her book "Dolphin Confidential: Confessions of a Field Biologist," Maddalena Bearzi, President of the Ocean Conservation Society, tells the story of the incredible day that a pod of dolphins stopped everything to save a human's life.

According to Bearzai, she and her research team were heading back to shore when a pod they'd been observing abruptly stopped feeding and swam to deeper waters -- unusual behavior for the species.

The researchers followed them, and after a few miles, the animals stopped, forming an eerie ring around a dark spot in the water. Bearzai tells the astounding story:

"Someone's in the water!" yelled my assistant, standing up and pointing at the seemingly lifeless body of a girl. For a moment, we were silent. Then, slowly, I maneuvered the boat closer. The girl was pallid and blonde and appeared to be fully clothed. As the boat neared, she feebly turned her head toward us, half-raising her hand as a weak sign for help.

While the dolphins circled around like bodyguards, the scientists sprang into action, pulling the hypothermic girl on board and wrapping her in a blanket to warm her. They couldn't even communicate with her, because she was German and no one spoke the language, but it became clear later that the incident was an attempted suicide.

Happily, the girl was rushed to the hospital and revived, and eventually thanked her rescuers -- if the dolphins hadn't led them to her, she would have died.

The scientists couldn't find an explanation for this incredible behavior, but stories like this aren't unheard of. In one stunning anecdote, a pod of dolphins intervened to protect a wildlife filmmaker from becoming a huge hammerhead's next meal: