Could a sperm whale bite off just the bottom half of one leg? I would think that if your legs were anywhere near a chomping whale that you’d lose more than that.
First, possibly. I don’t know.
Second- nitpick- IIRC Ahab’s leg was not bitten off. Moby Dick had become snarled n various ropes. As he swam past a trailing harpoon severed the leg.
Sperm whale teeth aren’t really intended for cutting/tearing. They are in the bottom jaw only and are widely seperated. You wouldn’t want one of those in your leg, but you would probably get “only” one. (Or two as a matching “flesh wounds”.)
Those poor gnomes.
Are you sure? Every reference I’ve seen says it was bitten off. Where does it say it was a harpoon injury?
It has been a while since I read Moby Dick. I no longer own a physical copy. I shall have to search through the text on the web,
Found it. Chapter 41.
His three boats stove around him, and oars and men both whirling in the eddies; one captain, seizing the line-knife from his broken prow, had dashed at the whale, as an Arkansas duellist at his foe, blindly seeking with a six inch blade to reach the fathom-deep life of the whale. That captain was Ahab. And then it was, that suddenly sweeping his sickle-shaped lower jaw beneath him, Moby Dick had reaped away Ahab’s leg, as a mower a blade of grass in the field.
Crap. I admit my error. But, I know there is a scene in the book where somebody is severely injured not by Moby Dick, but by a harpoon trailing behind him. I cannot recall if it was Captain whatsisname who lost a hand, Fedallah, somebody during the three day hunt at the end, or somebody else. Bah.
I would think a whale could simply tear off a man’s leg without having to bite all the way through it. Moby simply gripping Ahab’s leg in his mouth would only need a sudden movement to separate the leg at the knee.
Apparently they will bite to defend themselves:
My problem is, ISTM, is that for a sperm whale biting off just the bottom half of a leg seems like such a dainty bite.
Not that it makes a difference, but do you think Moby intended to just remove Ahab’s lower leg?
I would expect that to be Captain Hook…
Melville probably thought it would look silly if he described the whale as having nibbled Ahab’s leg off.
What are they for? They are so odd.
Having never actually seen one, that photo almost looks like AI. 
When I first saw this thread title, I thought it was going to be about whale sushi.
I cannot remember the name of the captain or his ship. Whenever the Pequod would meet another ship, Ahab would shout from the deck “Have you news of the white whale?” Everybody would say no. Ahab would go back to his cabin. Except the one time when the captain of the other ships holds up hammer strapped to his wrist in place of a hand and says “Seest thou this?” Ahab immediately wants to to go over to the other ship and talk. He cannot climb a rope ladded with one foot. They find a way to get him up to the deck of the other ship. The one-handed captain tells how he lost his hand in a meeting with Moby Dick.The one-handed captain extends his hammer prosthesis to say good bye. Rather than shaking it with his hand, Ahab raises his peg leg to touch it. Ishmael says (roughly) ‘It was the secret handshake of a very exclusive and undesirable club.’
Gilbert asks it better than I could.
My mistake. Captain Hammer then, I guess.
Ishmael’s take on it is hilarious, though.
Grabbing and holding soft-bodied squid for swallowing without chewing.
I think the damage you see on the whale’s head below is from numerous battles it has had with squid: