Growing up with a severe stutter, Alan Rabinowitz felt damaged and alone. Talking to adults had become so traumatic, he often said, he found solace by retreating to his bedroom closet, where he kept a chameleon, snakes, a turtle and a gerbil. Speaking to his pets came more easily. They did not make him feel worthless, and were as voiceless as he was in the human world.

On visits to the Bronx Zoo with his father, Alan gravitated to the old Lion House, with its rows of big cats roaring inside their cages. He found joy in talking to them as well, especially an old jaguar, who was wary and watchful.

“I would sit and whisper to this jaguar, outpouring all my emotions,” Dr. Rabinowitz said in an interview with Natural World Safaris, a tour operator, “and I promised that if one day I found my voice I would become their voice.”

He kept that promise.

With therapy he found his voice — a particularly forceful and articulate one — as a leading big cat conservationist for the Wildlife Conservation Society, which runs the Bronx Zoo, and, since 2006, for Panthera, the wild cat conservation organization that he co-founded.