Jonah was a figure in Earth history who encountered misfortune at sea, (AUDIO: Jonah) and survived being caught inside a whale. Though Peri Brown believed Jonah was merely a myth, the Sixth Doctor claimed to have met the man, describing him as a "nice chap". After getting swallowed by the whale, Jonah looked like old parchment, as his skin was "white, bleached and wrinkled".
After Bliss mentioned not wanting to be the "next Jonah", the crew of the Bloodhound began calling their captain, the Eighth Doctor, "Captain Jonah". The name stuck, and the Doctor grew fond of it. (AUDIO: Jonah)