Categories
Evolution

Quadrupedal Human Gait (repost 09/2010)

Quadrupedal Humans
Quadrupedal Humans

Bipedalism (walking upright on two limbs) in hominids is considered a logical and efficient means of locomotion arrived at via hundreds of millions of years of evolution. At the newly instituted PLOS group of blogs a thorough post appearing on the newly moved blog Neuroanthropology describes Turkish individuals who are quadripedal and exhibit what is called Uner Tan Syndrome (UTS). There is some conjecture on the cause of this condition and on whether or not it is evolutionary atavism.

This syndrome was first discovered in 2005 by √úner Tan of Cukurova University in Turkey who is also a member of the Turkish Academy of Sciences.

I note that the quadripedal humans seem to be scurrying along at a fair clip. They are not wearing any coverings on their hands. From the photo it is difficult to determine what they wear on their feet. The video below does show some foot gear. At least some of the quadrupedal humans seem to have the forelimb contact on the heel of the hand, but others may contact further foreward.¬† I’m sure this will be looked at closer. Evolutionary analysis and better coaching may lead to improved 4 limb locomotion for these individuals. So far I have not come across any reports of any quadrupedal long distance endurance events.

This does appear to be a real syndrome however and the blog describes the symptoms and results of MRI and PET scans on subjects. The findings include:

“signs of cerebellar dysfunction including: intention tremor, dysdiadochokinesis (inability to execute rapidly alternating movements particularly of the limbs), dysmetria (lack of coordination of movement typified by under- or over-shooting the intended position), and nystagmus (involuntary rhythmic eye movement, with the eyes moving quickly in one direction, and then slowly in the other). However, the cerebellar signs are relatively mild, and they are no more pronounced in the quadrupeds than in the one affected brother who walks bipedally.”

My take on this is that the syndrome appears to be an inherited motor and sensory issue (HMSN). There are many disorders in this category with a variety of symptoms. Some of the more common ones include Refsum’s syndrome and Charcot-Marie-Tooth disease .

Both a BBC and PBS Nova documentary have been produced on this condition.

Links:

Neuroanthropology Blog Post on “Human Quadrupeds” by Greg Downs – thorough discussion, many reference links

John Hawks Discussion on “Turkish Tetrapods” in 2006

A New Syndrome With Quadripedal Gait Tan, U. Int J Neurosci. 2006 Mar;116(3):361-9.

Family That Walks on all 4s (NOVA show)