In 2005, scientists around the world discovered the Ulas family in rural Turkey. Many of the children in the family walked on all fours instead of upright. It had never been seen before in modern humans: they bear crawled, reminiscent of Mowgli in the Jungle Book or most young kids, but continued doing so into adulthood.

The Ulas children were quadrupeds. Six children out of 18 in the family were quadrupeds, but sadly, one later passed away. It was such a shocking discovery that it was kept secret as “potentially dynamite,” as evolutionary psychologist Nicholas Humphrey put it. 

“The find was so unusual, it was decided to keep it secret,” says a 2015 documentary, which also states the family “shouldn’t exist.” (See video below.)

The Ulas family lived in a predominantly Islamic country where creationism is heavily favored over the idea of evolution.

Did the Ulas Family Turn Back Evolution 4 Million Years?

Had a genetic mutation turned back the clock 4 million years to when humans are thought to have evolved to walk upright? Was this family a “living missing link?” Scientists wanted to find out, immediately.

Ironically, the family’s existence became known from an unpublished paper by Turkish scientists. Rather than focus on the family’s habit of bear crawling, the paper focused on their impaired hand skills, overlooking the glaring significance of quadrupedalism.

It shocked Humphrey they didn’t focus on the obvious: “Scientists have never seen anything like this before,” he said.

Related: Scientists Discover a Switch Causing a Gorilla’s Brain to Grow More Like a Human’s

Some scientists suggested the family exhibited ancient genes that had resurfaced, possibly like those in primitive humans. There are other examples of it happening before. For example, people with congenital hypertrichosis are born covered in hair, including their faces. Occasionally, people are born with vestigial tails; about 1-5% of people have extra nipples.

The Ulas Family Was Subjected to Ridicule and Insults

While the documentary on the BBC suggested the Ulas family had “devolved,” Humphreys found such a notion deeply insulting and unscientific. No, he didn’t think they were “living fossils” as others cast them.

“My heart goes out to them,” Humphreys said. “It’s an amazing thing to see these people. They’re so familiar; they’re human like ourselves, and yet, in many ways, they’re walking in a way which no humans, no adult humans, have walked for two, three million years.”

As the documentary shows, the children’s parents were second cousins, and their brain’s cerebellum was unusually small. Testing indicated limited language, manual dexterity, and developmental skills. But other people with similar brain impairments never walk on all fours. Even one man born without any cerebellum walked upright.

The Kids Were Free to Bear Crawl at Home

Walking this way is extremely challenging, which is why the “Bear Crawl” is an endurance exercise for US Marines. But why were the Ulas children doing so? In their village, they were outcasts, ridiculed and tormented by others for their differences. But at home, they were free to bear crawl.

One of the family, Hussein, had been walking on his hands and feet for 28 years with tough callused hands. He could outrun many people with ease. But he and his sisters, between 18 and 34 at the time, found it challenging to walk upright.

As it later turned out, no one had strongly encouraged or helped them walk upright as youths. But, when given access to physical therapy as adults, parallel bars, and a walker, some began slowly standing. However, older Hussein found it more challenging.

Video by 60 Minutes Australia about the Ulas family:

Scientists’ Evolving Conclusions

Early on, some scientists quickly concluded that walking on all fours could be an inherited trait due to mutations. German researchers suggested a patch of DNA where they believed the mutation could be found.

A Turkish evolutionary biologist, Üner Tan, who postulated “reverse evolution,” performed tests in the home and later concluded the Ulas children had a condition later named Uner Tan Syndrome. He saw them as a “live model for human evolution.”

“Uner Tan syndrome (also known as Cerebellar Ataxia, Mental Retardation, And Dysequilibrium Syndrome, CAMRQ) is a collection of recessive single gene disorders in which affected individuals show quadrupedalism, mental retardation and cerebellar developmental defects,” a 2023 study states.

A Quantum Leap in Evolution to Bipedal?

Other researchers at Liverpool University studied how the affected children’s skeletal movements compared to those of apes. Yet the children walked on the heel of their hands and wrists, protecting their fingers, unlike apes. Perhaps this was what our ancient ancestors did, too, they suggested.

But if the Ulas children were walking on all fours because of genetic mutations, wouldn’t this suggest a sudden “quantum leap” in evolution 4 million years ago? Humphreys asked. If so, it contradicts how evolution over millions of years is currently understood. Instead, it suggests a sudden leap to becoming bipedal.

“It doesn’t make sense because it implies the development of being bipedal came about in a kind of quantum jump,” Humphrey said.

The mutations affecting the brain do point to extraordinary adaptivity for the Ulas children, while a quantum evolutionary leap raises so many other questions.

Related: Ancient Beings May Have Pondered the Afterlife Over 300,000 Years Ago

Video by Sterling Documentaries about the Family that Walks on All Fours: