Study: Bigger Balls = More Cheating
Norwegian researchers have conducted a study that found primates with larger testicles are more likely to be unfaithful to their partners.
Researchers from the University of Oslo studied various primates and found difference in testicle size has a direct correlation with fidelity– in both males and females. While male primates with larger testes cheated more, so did their female partners.
“We can determine the degree of fidelity in the female by looking at the size of the male’s testicles,” assistant professor Petter Bøckman is quoted in Britain’s Telegraph.
“If the male will only fertilize one female and has no competitors, he only needs sufficient sperm to reach the egg,” Bøckman continued. “If the female mates on the side, it is smart to have as many cars as possible in the race.”
“Then, the male must have testicles that are as large as possible,” Bøckman said.
The researchers found that bonobos, which have relatively large testicles, mate in groups, while gorillas, whose testes are relatively small, have a smaller number of partners.
“In gorilla troops, there is only one male,” explained Bøckman. “Even though the gorilla has a small harem, he has no need for large testicles– his balls are tiny.”
Human testicles are 50 percent larger than those of a gorilla.
“This testifies with abundant clarity to life in our flock,” asserted Bøckman. “We can pledge our fidelity until we are blue in the face, but this is evidence our females are cheating.”
“We are not like chimpanzees, where the female has four or five sexual partners every time she is in heat, but there is always a certain likelihood that the neighboring male has dropped by.”
The University of Oslo study comes months after researchers at Emory University in Atlanta, Georgia published a study that found men with smaller testicles make better fathers.
“Father’s testicular volume and testosterone levels were inversely related to parental investment and testes volume was inversely correlated with nurturing-related brain activity when viewing pictures of their own child,” anthropologist Jennifer Mascaro, the study’s lead researcher, wrote.
According to researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, only about three percent of mammalian species are monogamous. That figure rises to around 15 percent of non-human primates, and among the approximately 560 different human societies listed in Murdock’s “Atlas of World Cultures,” just 17 percent of those societies are “in some way socially monogamous.”
Tagged bigger balls more cheating, infidelity, Jennifer Mascaro, Max Planck Institute for Evolutionary Anthropology, Petter Bøckman, testicle size, testicle size fidelity, testicles, University of Oslo, Why do men cheat?, Why do women cheat?