I'm so sorry to the OP that this happened to their child. It must have been very scary for everyone involved.
I'm hoping that everyone who reads this thread will understand a universal truth: No small children should ever be allowed to interact with animals without close supervision. Any animal. Adult humans tend to really forget how much animal psychology is dependant on size and dominance. A toddler has neither in their favor, and animals do not operate by a moral code.
Even the family dog could get tired of a loud infant pulling on it's ears enough to bite. I know because it happened to me when I was small. And I never EVER forgot to respect animals afterwards. Nor did I blame our dog, she was the sweetest thing in the world.