Cleveland Zoo officials said the cheetahs never approached the boy or his parents, who jumped in to rescue him.
The toddler fell into the cheetah pit on Saturday after his mother dangled him over the railing and he slipped out of her grasp, authorities said.
The boy injured his leg, Fox News Cleveland reported.
The TV station said the mother would be charged with the crime of child endangerment.
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"You just hear these screams, then all you could see is the adult that jumped in, got the child and then somebody pulled him out," a witness was quoted as saying.
"It was a heavier-set guy with the kid. They started screaming and that's when they started blocking everybody off," the witness said.
The zoo's executive director, Chris Kuhar, said the mother appeared to be at fault.
"Unfortunately, we have a number of eyewitness accounts that point to the strong likelihood that the child was dangled over the railing," Kuhar said.
A Cleveland Fire Department spokesman said the mother was holding another child when the boy fell.
The zoo closed the cheetah exhibit for the remainder of the day and said it would press charges against the boy's mother for endangering his welfare.