I was thinking of two things while walking: that my legs could not hold me anymore and that I wanted to see a coquí, Puerto Rico’s endemic frog. We had been within the green labyrinth of El Yunque, Puerto Rico’s tropical rainforest, for almost four hours. Although I wanted to look up and appreciate the plethora of stars, I kept my gaze down so that the flashlight on my head would light the way. Falling down on one of those paths, full of rocks and roots, while carrying a backpack full of scientific equipment, is not a pretty picture. There were times when I slipped, but still had not fallen. I was in the back of the line, walking slowly to see if I could spot a coquí, but without missing the pace of the team. "Look, Luis," Aura said after a while.