Am I the only one who couldn't stop laughing at the quote "It was suggested that he had been bitten by a hippopotamus while fishing"?
And yes, I do believe it is "hippopotamuses" (see http://www.askoxford.com/asktheexperts/faq/aboutgrammar/plur...)
My worst fishing experience involved snagging my brother in the cheek when he walked behind me. (Well actually it was his worst fishing experience, I thought it was awesome at the time.)
That kid was suggested to have been attacked by a fucking hippo, which means its common enough there that when someone walks into a hospital without an arm, people consider that the most likely reason.