Backwards evolution busted: People walking on all fours do not have “apelike” gait but have adapted

A new study shows that a group of humans made famous by a 2006 BBC documentary called The Family That Walks on All Fours are not exhibiting backward evolution to that of our ape ancestors, but have just adapted to this strange means of locomotion due to their brain conditions.

The family from remote Turkey, were discovered in 2005. Their hand walking is seen as a “disability”. Instead, it’s how they adapted to their unique and rare condition.

Walking on All Fours Is Not Backward Evolution, Study Shows | News.

The conditions is called Uner Tan Syndrome (UTS) and includes severe mental retardation with affected speech. They have trouble walking on two legs and balance with their extra limbs – their hands. Professor Uner Tan thought he found evidence of devolution in the family. This is now discarded based on new evidence.

“The Family that Walks on All Fours” – YouTube.

The concept of devolution or backwards evolution is thrown around especially by Creationists who don’t understand at all how evolution actually works. This throwback concept is deeply flawed. Evolution does not work like a ladder of progression or purposeful direction. Evolution is descent with modification. However, if an organism still carries a genetic adaptation that can be useful, it will be expressed.

Uner Tan Syndrome: History, Clinical Evaluations, Genetics, and the Dynamics of Human Quadrupedalism.

The first family was discovered in a small village near Iskenderun, and families were later found in Adana and two other small villages near Gaziantep and Canakkale. In all the affected individuals dynamic balance was impaired during upright walking, and they habitually preferred walking on all four extremities.

The cause of the condition is likely multifaceted and genetic. A high rate of inbreeding may play a role in manifesting the syndrome.

The new research finds that the pattern of walking in UTS carriers is NOT a throwback to the ways apes walked on all-fours but is different. Simply an adaptation, not an atavism.

“Although it’s unusual that humans with UTS habitually walk on four limbs, this form of quadrupedalism resembles that of healthy adults and is thus not at all unexpected,” Shapiro says. “As we have shown, quadrupedalism in healthy adults or those with a physical disability can be explained using biomechanical principles rather than evolutionary assumptions.”

Here is the study:

PLOS ONE: Human Quadrupeds, Primate Quadrupedalism, and Uner Tan Syndrome

Another evolution trope is again busted with additional evidence. Science evolves too as our information gets better.


More about this condition:

Human, quadruped: Uner Tan Syndrome, part 1 – Neuroanthropology.

2 legs good, 4 legs better: Uner Tan Syndrome, part 2 – Neuroanthropology.

  6 comments for “Backwards evolution busted: People walking on all fours do not have “apelike” gait but have adapted

  1. Lagaya1
    July 18, 2014 at 9:49 PM

    Would it really be “backwards” evolution, anyway? Maybe it would seem like a step backwards, but wouldn’t it still just be evolution? The word backwards implies direction and a goal. Nit picking, I know.

  2. Mark Cooper
    July 19, 2014 at 5:44 AM

    I saw this documentary and I seem to recall that the conclusion of the scientists then was basically what this new study shows. That there was some neurological problem and that they had adapted to this gait. Another hypothesis was that they had a developmental problem and had just never adapted to walking upright. I suppose it’s yet another case of the pop media pushing the more sensational story line. Crazy, I know!

  3. Bob
    July 19, 2014 at 9:18 AM

    Perhaps they work at the Ministry of Silly Walks.

  4. Artor
    July 19, 2014 at 5:08 PM

    I’m embarrassed that anyone who calls themselves a scientist would say these people walk “like apes.” Aside from the fact that we all walk like apes, because we are, of course. But as for walking like any of the non-human apes, obviously they don’t walk like that, since they’re not shaped like that. The other apes have short legs and long arms that allow them to knuckle-walk upright comfortably. Can you imagine the neck problems these people must have?

    Apes walk like apes because they are apes. Humans don’t because we are humans, no matter how badly inbred.

  5. ONe Eyed Jack
    July 20, 2014 at 1:02 PM

    Not nit picking at all. I had the same thought. It’s not a minor point. It’s a common misconception (not that Sharon intended to imply it) that evolution has a direction or goal.

  6. July 20, 2014 at 1:37 PM

    Obviously the backwards evolution idea is flawed. As I said, it is used by clueless Creationists. I was amazed it was suggested at all. Hearing that they have balance issues makes this unusual form of locomotion make more sense.

    Generally, people don’t think of other people as “apes” and would distinguish a human from a gorilla or chimpanzee. Only those with a zoological mindset bristle at it.

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