Researchers say in a new study that female bottlenose dolphins have a functioning clitoris that provides pleasure when stimulated. File Photo by Ken James/UPI | License Photo
Jan. 10 (UPI) -- Female dolphins have a functional clitoris that provides pleasure when stimulated, according to a study published Monday in the journal Current Biology.
Scientists have discovered a clitoris-like structure with sensory nerves and erectile bodies in the vaginal entrance of bottlenose dolphins, and researchers say that its location -- and previous animal observations -- suggests it could be stimulated during copulation.
Dolphins are known to be very social creatures that have sex throughout the year to forge and maintain social bonds, researchers say.
Previous studies have found that the clitoris in the vagina could make stimulation during sex likely, and there have been reports of females rubbing each other's clitorises with snouts, flippers and flukes.
Researchers, led by first author Patricia Brennan, an assistant professor of biological science at Mount Holyoke College in Massachusetts, analyzed clitorises from 11 female bottlenosed dolphins that died of natural causes.
The researchers examined the presence, shape and configuration of each of the erectile bodies, as well as the nerve fibers in the tissues.
They found was that the erectile bodies worked just like a human clitoris, and that they change shape as dolphins become adults.
"Just like the human clitoris, the dolphin clitoris has large areas of erectile tissue that fill up with blood," Brennan said in a press release.
Scientists found genital corpuscles similar to those found in the human clitoris and tip of the penis, and which are involved in the pleasure response during stimulation.
"Since the entire pelvis of dolphins is so different to humans, it was surprising to see how similar the shapes were," she says. "Also, the size of the nerves in the clitoris body was very surprising. Some were larger than half a millimeter in diameter."
Interest in the functionality of the dolphin clitoris stems from the evolution of research on dolphin vaginas.
Researchers know that dolphins have sex for bonding and fun, and that copulation methods differ between each dolphin species, but there is a lot they say they don't understand.
Dara Orbach, a researcher at Texas A&M University and research assistant at Mount Holyoke who has worked on several studies with Brennan, including the new one, said that learning how dolphin genitals align and function can help explain the role of sex for these animals.
"In other mammalian species with year-round copulation, such as humans and bonobos, sex is known to be pleasurable for females, often through clitoral stimulation that leads to orgasm," Orbach said in a 2019 press release.
"Our anatomical observations suggest the clitoris is functional in bottlenose dolphins, but further research ... [is] necessary to test if sexual experiences can be pleasurable for female dolphins," Orbach said.
Brennan said researchers have found "large clitorises" every time they dissected a dolphin vagina, but had not studied them in detail until now.
Overall, she noted that there is little study on the clitoris and female sexual pleasure in nature -- and the human clitoris wasn't fully described until the 1990s.
"This neglect in the study of female sexuality has left us with an incomplete picture of the true nature of sexual behaviors," Brennan said.
"Studying and understanding sexual behaviors in nature is a fundamental part of understanding the animal experience and may even have important medical applications in the future," Brennan said.