An ancient book of Chinese Confucianism "Raiki" ("Liji") first described Shojo as "a parrot can talk, but that is nothing but a bird; a shojo can talk, but that is nothing but an animal", and some annotations on "Raiki" explained that Shojo resembled large anthropoid apes such as orangutan (in the past, some Japanese called orangutan 'shojo'); in Japan, they had been given other characters, and became legend and even dramatis personae of traditional performing arts.
元来は礼記に「鸚鵡は能く言して飛鳥を離れず。猩々は能く言して禽獣を離れず」とあるのが出典で、後代の注ではしばしばオランウータンなどの大型類人猿に擬せられるが（猩々はオランウータンの和名のひとつでもある）、一方で各種の説話や芸能によってさまざまなイメージが付託されて現在に及んでいる。