Surprising reason human penises are so big revealed – are you bigger than a gorilla?

A SCIENTIST has revealed why human penises are so big in comparison with our closest living relatives.

Research has shown the average member measures around 5.2 inches when erect, whereas for chimps it’s only 3.1 inches.

Meanwhile, despite their size, gorillas only display an average of just 1.25 inches.

So why do humans boast larger manhoods in comparison?

Most scientists tend to agree the change was sparked when our species started to walk on two feet around four million years ago.

Simon Underdown, a professor of biological anthropology at Oxford Brookes University told the Mail becoming bipedal “almost certainly” led to the penis evolution.

He explained how becoming bipedal made it physically harder for sperm to reach the cervix during sex, which makes conception harder, and ultimately worse for procreation.

The expert said: “Chimps and other primates don’t need to be big because they’re not bipedal and hence getting things to the right location is not an issue.”

“Just think about how quick most animal mating is when you see it on David Attenborough documentaries,” he added. 

Professor Underwood said there was “massive” pressure for our species to transition to walking on two legs.

It allowed for holding and travelling with tools, as well as gaining an advantage on rival species.

This is believed to have happened around four million years ago, when there’s evidence of homo erectus.

Meanwhile, Mark Maslin, professor of palaeoclimatology at University College London, dubbed the human penis as “extremely dull” compared with other species.

In a piece for The Conversation, he said: “It does not have lumps, ridges, flanges, kinks or any other exciting feature that other primates have”.

And, while human penises are larger, the testicles are a lot smaller to primates in comparison.

Professor Maslin highlighted how a chimp’s testicles weigh more than a third of their brain – whereas humans’ are less than three per cent.

This is understood to be because of the frequency other animals mate.

According to the expert, male chimps will “have sex all the time with any female and with any excuse”.

“A female therefore may contain sperm from multiple partners at any one time, which puts the sperm itself – and not just the animals that produce it – into direct competition,” he added.

This has seen chimpanzees develop bigger testicles and produce more sperm throughout the day.

This comes as women have ranked men’s penises and revealed what they find most satisfying – and what could lead them astray.

A survey of 1,400 women took into account their opinions and determined what size is best in the bedroom.

Research from sexual health website Bad Girls Bible, revealed more than two-thirds wouldn’t be fully satisfied if their partner’s penis was less than four inches.

And nine in 10 women said they would not be satisfied with a penis between one and three inches – a micropenis.

On the other end of the scale, anything over nine inches was considered too big by over 50 per cent of poll takers.

The main reason cited was pain, as larger members can be uncomfortable, cause bruising, bleeding or tearing.

The disparity in sizes saw four in 10 women admitting they would be more likely to be unfaithful if their man’s member was too small.

But, over half would be more likely to end a relationship if it was too large, or the man was selfish in bed.

Researchers determined the “Goldilocks” measurements were between six and eight inches when erect.

New data has also shown how the average penis size in the UK has grown by 10 per cent in just two years.

The new figures put the UK in 8th place for global rankings for growth and marks an 8.9 per cent increase.

Sadly though, Britain’s penises tend to fall into the “grower not a shower” category as we still rank at 60th place for overall size.

Our men were overtaken by the Sudanese – whose average length at full mast is more than an incredible 7 inches.