Diver with southern right whale

Photograph by Brian Skerry

National Geographic: It must have been pretty nerve-racking having such a large animal swim up to you.

Skerry: It was amazing. I mean, I have to tell you there were days when I was at the bottom at 70 feet, and here comes this bus swimming down. I’m standing on the bottom, and as it comes down, I get on my knees, lean over backwards—my scuba tank is now digging into the sand. And of course their eyes are on the side of their heads, so it had to turn and look at me. It came within inches. Here’s this softball-size whale eye looking at me. But then it stops—stops on a dime. It’s just hovering there, and literally one flick of its tail, and it would have crushed me like a bug. But it doesn’t. It was just highly curious.