Researchers believe the five brothers and sisters, who can walk naturally only on all fours, may provide new information on how humans evolved from four-legged hominids to walk upright.
Humphrey, who has contributed to the documentary, believes the style of walking may be a throwback to a form of behaviour abandoned by humans more than three million years ago.
I'm sick of all this quadruped infiltration in our society. I can't identify with quadrupeds and therefore have no interest in what they do. I am sure the only people who care about quadrupeds are quadrupeds.
Does the fact I do not care about quadrupeds mean that I am borderline quadruped and that if I view their wicked lives I will be tempted to become quadruped?