Clyde is super cunning! And so far as I know, that is the actual subsection of US Copyright Office ruling about which species can and cannot hold a copyright. There was a bit in the news a few months ago where a wildlife photographer was suing Wikipedia to have them take down a photo that he said he had under copyright, but they said no, since the camera's button was actually pressed by a macaque, it's a monkey selfie and thus can't be copyrighted. What a world :D