Men With Larger Testicles Are More Likely To Cheat, Researchers Claim
Scientists say there is a correlation between fidelity and the size of a male's testicles. Researchers studied primates and found...
Scientists say there is a correlation between fidelity and the size of a male's testicles.
Researchers studied primates and found differences in testicle size were reflected in female fidelity.
They found bonobos, who have particularly large testicles, mate in large groups whereas gorillas have small testicles and have a smaller number of partners.
'We can determine the degree of fidelity in the female by looking at the size of the male’s testicles,' said Petter Bøckman of the University of Oslo, who led the study.
'If the male will only fertilise one female and has no competitors, he only needs sufficient sperm to reach the egg.
'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. In gorilla troops there is only one male.
Even though the gorilla has a small harem, he has no need for large testicles – his balls are tiny.
The team also studied the animals that have the largest testicles.
'Animals with short lifespans may have enormously large testicles,' the reasearchers said.
'In one type of grasshopper the testicles occupy half their body mass. The testicles are even larger in sea urchins.
They spawn directly into the ocean. To increase the chance of fertilising an egg, the sea urchin is a huge testicle with a little shell around it.
The testicles of humans are one and a half times larger than those of gorillas, the team said. They claim this shows that we are an unfaithful race by nature.
Prof Bøckman said: 'This testifies with abundant clarity to life in our flock.
'We can pledge our fidelity until we are blue in the face, but this is evidence that 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 neighbouring male has dropped by.
By Mark Prigg