This unusual photo ran in numerous papers in September 1963. I can't find a linkable example in the Google News Archive, but here it is in the Binghamton Press [PDF]. (A lot of examples of it come up in a search on newspaperarchive.com, but that's a paid archive, so I can't link to any of the results.)
The caption read:
All the animals are pretty tame at the Percy Pangborn Ranch above Lake Wenatchee in the foothills of Washington State's Cascade Mountains, Sept 14. 1963. A golden mantled ground squirrel chomps away on a nut as it rides around on the neck of a fawn.
The photo looks a little suspect to me. However, none of the papers it ran in raised any doubts about its veracity.
Back in the 60s, photo editors would often darken the outlines of figures in photos so that you could see them better when they ran in newspapers. To modern eyes, this can make "real" photos look manipulated. That might be the case with this photo. Perhaps the outline of the squirrel was darkened, which makes the squirrel look like it was pasted into the shot. But given the subject matter — a squirrel riding a fawn while eating a nut — I'm still suspicious.