Moby-Dick Questions Chs. 55-60: Why is “the great Leviathan” the “one creature in the world

Why is “the great Leviathan” the “one creature in the world which must remain unpainted to the last”? (p. 289 [218]) And what exactly does Ishmael mean by this statement?  Who comes closest to understanding a whale, and why?  Closely read the third paragraph of ch. 57 and the final paragraph of ch. 58.  Who is the “King of the Cannibals?”  Read closely the last two paragraphs of ch. 58; how do you interpret them?  Ishmael says on two occasions, “Who ain’t a cannibal?”  How does this statement compare with his statement in ch. 1, “Who ain’t a slave?”  What are the dangers of the line?