We’ve all been to the zoo. Some zoos do better than others at recreating natural habitats, so the animals they confine can enjoy the illusion of freedom.

Visiting one such zoo, I studied a female elephant in her enclosure. The elephant’s behavior puzzled me. She would step forward onto a horizontal log, and it looked like she was about to cross over it. Then her rear leg would lift and bend slightly. As if this slight movement had tugged a rope, she would stop, then step backward off the...

Read more