And I would argue that even if David Slater didn't fully intend for the monkey to take the photo, he had more intention or expectation for that happening than the monkey had for taking a photo. The monkey was only interested in the sound made by the camera, not in directing a photo shoot.
Well, it might be that the monkey wouldn't deserve copyright even if copyright could reside in a monkey. There are broad classes of works like phone books which don't get copyright at all:
