Moby Dick by Herman Melville Chapter 81 Page 30

Now, this occasional inevitable sinking of the recently killed Sperm Whale is a very curious thing; nor has any fisherman yet adequately accounted for it. Usually the dead Sperm Whale floats with great buoyancy, with its side or belly considerably elevated above the surface. If the only whales that thus sank were old, meagre, and broken-hearted creatures, their pads of lard diminished and all their bones heavy and rheumatic; then you might with some reason assert that this sinking is caused by an uncommon specific gravity in the fish so sinking, consequent upon this absence of buoyant matter in him.

But it is not so. For young whales, in the highest health, and swelling with noble aspirations, prematurely cut off in the warm flush and May of life, with all their panting lard about them; even these brawny, buoyant heroes do sometimes sink.