Evidence of a functional clitoris in dolphins

In species that copulate during non-conceptive periods, such as humans and bonobos, sexual intercourse is known to be pleasurable for females. Dolphins also copulate throughout the year, largely to establish and maintain social bonds¹. In dolphins, the clitoris is positioned in the anterior aspect of the vaginal entrance², where physical contact and stimulation during copulation is likely. Clitoral stimulation seems to be important during female-female sexual interactions in common bottlenose dolphins (Tursiops truncatus), which rub each other's clitorises using snouts, flippers, or flukes³. Determining a sexual pleasure response in animals not amenable to neurobehavioral examination is difficult, but investigation of the clitoris may elucidate evidence of functionality. In this study, we assessed macro- and micromorphological features of the clitoris in common bottlenose dolphins to examine functional features, including erectile bodies with lacunae, extensible collagen and/or elastin fibers, and the presence and location of sensory nerves. Our observations suggest the clitoris of dolphins has well-developed erectile spaces, is highly sensitive to tactile stimulation, and is likely functional. VIDEO ABSTRACT.