Thumbs, tools, and early humans.
McGrew
W C
WC
D000818:Animals; D001696:Biomechanical Phenomena; D005580:Fossils; D049690:History, Ancient; D015186:Hominidae / Q000033:anatomy & histology*; D006801:Humans; D009048:Motor Skills; D013933:Thumb / Q000033:anatomy & histology*