He was weeding a lily pond on Monday, standing in about 4 feet of water, when he apparently stepped on the 392-pound male alligator, Capt. Roy Brown of the Florida Fish and Wildlife Conservation Commission said.
"He did recall that the alligator obviously grabbed his arm, there was a twisting type action," the doctor said.
The alligator was a wild alligator that lived at a nearby pond and occasionally wandered into the lily pond at the botanical garden, where workers called it Mo-Jo.
Goodman told wildlife officials he did not see the alligator until it attacked.
They said the alligator might have mistaken Goodman's splashing the pond for that of a duck or wading bird, their natural prey. Because it was used to being around people, it had probably lost its natural fear of humans, Brown said.