Testis asymmetry in the dark-spotted frog Rana nigromaculata.

The article focuses on testis asymmetry in dark-spotted frog Rana nigromaculata. Testis asymmetry is common in some animals and it was explained that this happens because one testis grows more to compensate for the reduced function of the other testis. The authors conducted the study with the goal of testing whether frogs possessed significant differences in left and right testes size. The male R. nigromaculata were collected in northeastern Sichuan, western China and the testes comparison was done using a paired t-test. They found that the R. nigromaculata's left testes were significantly larger and added that it was much larger in larger and older male dark-spotted frogs.