Robert Lee Hotz has a great article in WSJ on the phenomenon of papers with long author lists (in a recent case, this list is over 24 pages long -- in fine print!). His articlle has a plot that shows that 2012 saw over 200 papers with 1000+ authors!
Hotz also goes on to discuss some of the pranks played by scientists:
Michigan State University mathematician Jack Hetherington published a paper in 1975 on low temperature physics in Physical Review Letters with F.D.C. Willard. His colleagues only discovered that his co-author was a siamese cat several years later when Dr. Hetherington started handing out copies of the paper signed with a paw print.
In the same spirit, Shalosh B. Ekhad at Rutgers University so far has published 32 peer-reviewed papers in scientific journals with his co-author Doron Zeilberger. It turns out that Shalosh B. Ekhad is Hebrew for the model number of a personal computer used by Dr. Zeilberger. “The computer helps so much and so often,” Dr. Zeilberger said.
Not everyone takes such pranks lightly.
Immunologist Polly Matzinger at the National Institute of Allergy and Infectious Diseases named her dog, Galadriel Mirkwood, as a co-author on a paper she submitted to the Journal of Experimental Medicine. “What amazed me was that the paper went through the entire editorial process and nobody noticed,” Dr. Matzinger said. When the journal editor realized he had published work crediting an Afghan hound, he was furious, she recalled.
Physicists may be more open-minded. Sir Andre Geim, winner of the 2010 Nobel Prize in Physics, credited H.A.M.S. ter Tisha as his co-author of a 2001 paper published in the journal Physica B. Those journal editors didn’t bat an eye when his co-author was unmasked as a pet hamster. “Not a harmful joke,” said Physica editor Reyer Jochemsen at the Leiden University in the Netherlands.