Several years ago, Dr. Leal was studying competition between two species. If he removed all of the trunk-ground anoles, he wondered, would the trunk-crown lizards extend their territory farther down the tree? He ran into a problem, however. He would take the trunk-ground lizards far from their home territory to make room for their upstairs neighbors, and then release them. But in a reptilian version of the children’s song, “The Cat Came Back,” the lizards wouldn’t stay away. “Lizards kept showing up in the territory that had just been scoured for lizards,” he said.

Dr. Leal wondered whether new anoles were appearing in empty territory or the old ones were returning. But how could a lizard that had never left home find its way back through 25 yards or so of dense rain forest?

First, he established that they do find their way back. A graduate student would take one, put it in a box, shake it to disorient the anole, walk about 80 yards or more away in a randomly chosen direction, shake the box again and let the lizard out. “The graduate students got lost,” Dr. Leal said, but not the lizards. It took them a few hours or a few days, but about 80 percent of them found their way back.