what are some anatomical features of moby dick seen by the sailors

“Does he fan-tail a little curious, sir, before he goes down?”

“And has he a curious spout, too,” said Daggoo, “very bushy, even for a parmacetty, and mighty quick, Captain Ahab?”

"... his spout is a big one, like a whole shock of wheat, and white as a pile of our Nantucket wool after the great annual sheep-shearing; aye, Tashtego, and he fan-tails like a split jib in a squall."