Sturdy shoes first came into widespread use between 40,000 and 26,000 years ago, according to a US scientist.Humans' small toes became weaker during this time, says physical anthropologist Erik Trinkaus, who has studied scores of early human foot bones. He attributes this anatomical change to the invention of rugged shoes, that reduced our need for strong, flexible toes to grip and balance. The research is presented in the Journal of Archaeological Science. The development of footwear appears to have affected the four so-called "lesser" toes - excepting the big toe. Ancient footwearWhile early humans living in cold northern climates may...