Humpback whales are massive animals that are very social and seem to be quite intelligent. When scientist Nan Hauser was swimming in the ocean and studying a pod of humpbacks, she was hoping to learn more about them, but she got more than she bargained for.

At one point, she saw that one of the whales began charging right at her. This is an odd thing to do for a while, not to mention terrifying.

When it got close enough, it seemed to be trying to pull Hauser in under its fin, once again, an unheard-of behavior for the whales. At this point, she was getting scared since the whale is so massive, and it has sharp barnacles all over that could slice her up.

The whale wasn’t quite done with her, though. Next, it maneuvered around to get Hauser on its back and pushed her up out of the water, moving her along. She tried to swim away multiple times, but the whale was not giving up.

Eventually, the whale let her get away, and it was at this point that she figured out what was going on.

She looked over at the other whales and saw them smashing their tails against the water in an unusual way. Moments later, she saw a massive tiger shark that the whales were trying to get to go away. In an interview with BBC Earth, Hauser explained:

“I’ve spent my entire life underwater and I’ve seen plenty of tiger sharks. This was like a truck. This was a huge tiger shark, and it was coming right for me.”

As far as she can figure out, the tiger shark was stalking her to try to attack when the humpback whales decided to save her life. One whale went directly to protect her while the others drove the shark away. Of course, it is impossible to know the motivation of the whales, but that is the only explanation Hauser explains:

“I still to this day can’t believe it happened and being a scientist it’s even harder. If someone told me this story, I wouldn’t believe them.”

As if that story weren’t heartwarming enough, it gets even better by the fact that just over one year later, Hauser got a call over the radio saying that someone had spotted the whale that saved her life. She quickly got on the boat and went out to see for herself.

“And then next I knew the whale came up next to the side of the boat. He ignored everyone else on the boat, and he stared directly at me… I looked at him, and I saw a scar on his head, and I just screamed ‘he’s back I can’t believe it he’s back!’ and sure enough there he was.

I just whipped on my wet skin and slid [into the] water and I swam down next to him and he opened his eyes and he just looked at me and kept nudging me… It was like seeing your dog that you haven’t seen in six months.”

Whales can live a long time, so it is certainly possible that these two will be able to meet up again in the future to continue their odd, but amazing, relationship.

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