citVibrators can be used, in a stimulating way, to study the sex of turtles. This study tells how.
“Good Vibrations: A Novel Method for Sexing Turtles,” Donald T. McKnight, Hunter J. Howell, Ethan C. Hollender, and Day B. Ligon, Acta Herpetologica, vol. 12, no. 1, 2017, pp. 117-121. The authors, at Missouri State University, James Cook University, and Towson University, report:
“While most species of turtle exhibit secondary sexual dimorphisms that can be used to reliably infer sex, there are some species that are very difficult to sex, and even within many dimorphic species, it is not uncommon to encounter individuals that appear to exhibit both male and female secondary sex characteristics. Therefore, we tested the novel method of using a vibrator to sex turtles by stimulating male turtles to evert their penises. We tested this method on males of four species (three families) with known sexual dimorphisms: spiny softshell turtles (Apalone spinifera; n = 14), western chicken turtles (Deirochelys reticularia miaria; n = 17), Mississippi mud turtles (Kinosternon subrubrum hippocrepis; n = 10), and common musk turtles (Sternotherus odoratus; n = 9). The method accurately sexed 100% of A. spinifera, 64.7% of D. r. miaria, 80.0% of K. s. hippocrepis, and 55.6% of S. odoratus.”
Sternotherus odoratus, which remains difficult to sex, is also known as the “stinkpot turtle.”
BONUS: A performance, by humans, of the song “Good Vibrations”:
UPDATE: Jason Bittel has further details, in the Washington Post: “This $10 sex toy is helping scientists study turtles“