“Do Female Bonobos Fake Orgasm?” ask Wolter Seuntjens and Karolina Hansen (pictured here), going on to explain that they would like to know the answer. Details are in their paper (which you can read in its entirety):
“Do Female Bonobos Fake Orgasm?” Wolter Seuntjens and Karolina Hansen, Journal of Unsolved Questions, vol. 1, no., 15, 2011.
BONUS: Walter Seuntjens’ earlier masterpiece, “On Yawning; or, The Hidden Sexuality of the Human Yawn“, was published in volume 11, no. 1 of the Annals of Improbable Research. It’s a a specially abridged version of the Ph.D. dissertation which the author defended (successfully!) on October 27, 2004. The related web site www.baillement.com is a lavish compendium of information about yawning.
(Thanks to investigator Martin Gardiner for finding this.)