A study of the feet of nearly 398 visitors at the Boston Museum of Science has revealed that one out of 13 people have flexible ape-like feet.

Scientists found that when apes lift their heels off the ground their feet are floppy with nothing holding their bones together. This is known as a midtarsal break, and surprisingly was found in some of the participants by the Boston team of scientists.
Many of the participants with flexible feet were not aware of it.
The American Journal of Physical Anthropology has published this research.
Source-Medindia