"The tortoises didn’t seem to distinguish between me—a National Geographic photographer—and a frigatebird or a coconut crab or a flightless rail. We were all part of the ecosystem, and they treated humans as they treated every other creature: They ignored us. When we left our hut doors open, which we often did to let in air, the tortoises would walk right through. It didn’t matter if we were cooking or sleeping or preparing camera gear. Our quarters were part of the daily migratory highway. When we sat on a small sandy patch behind the hut to eat, the tortoises would try to walk over us, almost bulldozing us out of the way. That’s how much they feared humans."