Feral children in mythology and fiction are often depicted as having superior strength, intelligence and morals to "normal" people, the implication being that due to their animal upbringing they represent humanity in a wild and uncorrupted state.
Thus Romulus and Remus, raised by a wolf, became the founders of Rome; Rudyard Kipling's Mowgli, also raised by wolves, becomes the natural ruler of the jungle. He might be seen as a metaphor for the British Raj - a member of a "superior" race whose destiny is to rule the "inferior" races; a jungle version of the white man's burden. Edgar Rice Burroughs' Tarzan, raised by apes, has become an iconic hero of novels, comic strips and motion pictures; he may have been suckled by an ape but there is never any doubt that he is on the side of the angels.
Other stories featuring children raised by animals, possibly influenced by Mowgli and Tarzan, include Shasta of the Wolves (1919) by Olaf Baker, in which a Native American boy is raised by a wolfpack in the Pacific Northwest, and Jungle-Born (1924) by John Eyton, in which a boy raised by apes in northern India inadvertently saves a teenage girl from her abusive father.
British comic books of the 1960s and 1970s seemed particularly fond of wild child stories. "The Wild Wonders" in Valiant (fl 1970s) are two boys lost on a Scottish island and raised in the wild, developing their own language; returned to civilisation at about the age of 10, they become superb athletes and enjoy many comic adventures.
In "Fishboy", written by Scott Goodall (uncredited), (1968 - 1975 in Buster), the eponymous hero was abandoned on a remote island as a baby, implausibly learned how to breathe underwater and to communicate with sea creatures, and grew webbed fingers and toes.
Goodall also created "Kid Chameleon" (1970-1972 in Cor). Raised by reptiles in the Kalahari Desert after the murder of his parents, Kid Chameleon wears a suit of lizard scales that can change colour to camouflage him like his namesake the chameleon (actually his camouflage is much better, because the artist simply lets the background colours show through his outline, making him almost invisible). In keeping with the heroism of feral children, both Fishboy and Kid Chameleon spend most of their time using their special abilities to help people in trouble and defeat stereotypical villains.
More recently, the title character of Miyazaki Hayao's 1997 anime film Princess Mononoke (real name San) was raised by a wolf god. San is drawn into a deadly conflict between the forest gods and the humans whose presence seems to threaten them.
Jane Yolen's Passager (1996), the first of the Young Merlin trilogy of short novels, depicts a slightly more realistic view of feral childhood. Abandoned in a Welsh forest at the age of 7, the boy who will become Merlin lives wild for a year as little better than an animal, until a falconer who is used to taming wild things captures him and begins the long and difficult task of re-educating him in human behaviour.
The French comic book (bande dessinée) Pyrénée (1998), by Regis Loisel and Philippe Sternis, features a girl who is raised by a bear and taught wisdom by a blind old eagle in the French Pyrenees. This story has won critical acclaim, but has also drawn some criticism because the girl is naked - a factor which might prevent the comic from appearing in English translation, especially in America.
Further Reading: Mother was A Lovely Beast (subtitled 'A Feral Man Anthology Fiction and Fact About Humans Raised By Animals) edited by Philip José Farmer (1974)