He also observed: “For nearly every disease I saw at the zoo, the simple question of why certain species, human or nonhuman, are susceptible to it, while others are not, raised immediate possibilities for research. Nearly every day at the zoo, the veterinarians and I would make fascinating, unexpected connections between human and veterinary medicine.”

In an interview, he said the stint at the zoo inspired new respect for the complexity of veterinary medicine. “I really had to overcome some bias that I think pervades much of medicine, that human physiology and disease is unique and that veterinary medicine does not have much to teach us,” Dr. Evrony said.

He and other students in the elective said they were repeatedly struck by how much they learned from treating species other than their own.

Dr. Travis Zack, now a resident in internal medicine at the University of California, San Francisco, said he gained new insights into a rare form of human chronic lymphocytic leukemia by treating the zoo’s 13-year-old black swan, Merlot, for the same disease. The swan appeared to be responding well to a human leukemia drug.

“We think of these as human diseases, but they’re really diseases that occur across the animal kingdom,” said Dr. Zack, who also has a doctorate in biophysics, and works at the Broad Institute, a genetics research institute affiliated with Harvard and MIT.