"People will actually chuck coins right into their mouths," she said. "They don't have a spitting reflex like a mammal, so the next time they eat anything, they'll swallow them."
The alligator isn't the first animal to die because of foreign objects, D'Agostino said.
Brindle, a seal, died of metal poisoning in June 2007. When the seal was examined after death, 92 coins were discovered in her stomach. Her stomach acid triggered a reaction with the zinc in pennies. The toxic result was kidney failure.
Like the alligator exhibit, visitors sometimes throw money into the pool to make a wish. Coins that spin as they sink reflect sunlight, mimicking the appearance of a fish, D'Agostino said.
The effect is a lot like that of a fishing lure.
Keepers now X-ray the seals and sea lions twice a year. Any debris is removed.
But checking the alligators isn't so easy, D'Agostino said. Their stomachs can't be X-rayed. Each scale has a bone inside, so the armor prevents veterinarians from seeing beyond the scales.
An arthroscopic camera reveals the stomach contents, but anesthetizing, scoping and evaluating the alligators several times a year isn't ideal.
So zookeepers are working to educate the public about animal health and safety, she said.
They may modify the exhibits a bit to catch some of the falling debris.