A Siamese cat co-signed a physics paper in 1975

In 2014 the American Physical Society announced that papers signed by cats would be free to read for ever. It was an April Fool's joke, but the paper existed: a Siamese cat signed one in 1975 and it is still in the archive.

Thirty-four years before that joke, in 1980, the French science magazine La Recherche published a piece on helium credited to one F. D. C. Willard, this time with no co-authors. Willard did not answer readers' letters.

And five years before that, in 1975, Jack Hetherington, a physicist at Michigan State University, finished a paper on the behaviour of helium-3 at very low temperatures and showed it to a colleague before sending it to Physical Review Letters. The colleague spotted the problem in two minutes: Hetherington had written “we” and “our” from start to finish, and the journal sent back single-author papers written in the plural. Fixing it meant retyping whole pages, which in 1975 meant a long afternoon at a typewriter.

Hetherington took the other way out and added a second author. F. D. C. Willard was his Siamese cat, Chester: Felis Domesticus Chester, with Willard after the cat's father. The paper was published exactly as it stood. Hetherington signed some reprints with an inked paw print, and Chester never claimed his share, though he never wrote the second half either.