I think the photographer should own them. I can see where they are coming from with animals being unable to hold copyright; but to my mind it would then have to apply to images taken from a remote camera device - such as documentaries where the camera is attached to an animal with no actual human interaction once attached. I'm pretty sure National Geographic would have something to say about that.
It's no different to a remote controlled camera to my mind - the shutter might not be pressed by a photographer standing next to the camera, but he has made all the effort to ensure things are set up for the photo (and may well have spent heavily to make it possible).
There's the right way, the wrong way and the railway.