C. S. Lewis’ The Voyage of the Dawn Treader, book three of the Narnia series, features the island of the Dufflepuds, who do this. Terry himself traces the story back much further:
“Two things influenced this. One is that, in accounts of very early long-distance voyages, ‘people who go around on one foot’ are among the usual freaks encountered (memory creaks, and recalls some about them in The Saga of Eirik the Red…). The other is that, when I was a kid, I’ll swear we had a class reader of Robinson Crusoe and a pic showed him in his goat skins marvelling at the one footprint he’d found in the sand. The illustrator had obviously been told to draw the picture of RC finding ‘a footprint’ and had done just that.”