However, Nicholas Humphrey, who accompanied the documentary makers, concluded that it was due to a rare set of genetic and developmental circumstances coming together. First, their mother recalls that initially all of her 19 children started off walking with a bear-crawl (i.e. on their feet rather than their knees).
Nicholas Humphrey, who accompanied the documentary makers, concluded that the unusual walking pattern was due to a rare set of genetic and developmental circumstances coming together. The mother's recollection is that all of her 19 children started off walking on their feet rather than using their knees.