I'm no expert on photo-fakery, but those guys look authentically 1900ish to me- as does the style of the image. The beast is believable- and seems to be in the early stages of decomposition (so not recently shot).
But there's something weird going on with the background.To the right we have what looks like a barn door. To the left there's a surface with rungs embedded in it that might be concrete or plaster were it not for the waviness of the bottom edge. And where exactly does the barn door end and the other surface begin? Then there are the slanting features behind the legs of the guys to the left. One commentator suggests they're disembodied deer's feet- and proof that what we've got here is a picture of a boring old hunting party that has been whizzed about in the computer.
So almost certainly a fake... yes?