Whales, dolphins, and porpoises (cetaceans) are divided into two large groups (suborders)-baleen and toothed.
The largest group, containing the largest whales, is the baleen whales: blue, fin, right or bowhead, humpback, and minke whales, among others.
These animals have flat flexible plates with frayed edges arrayed in parallel rows,
sieve-like structures composed of comb-like thick hairs made of keratin (a common biological substance similar to fingernail material).
They erupt to form upper jaw filtration curtains used to strain plankton from seawater.
The largest toothed whale is the sperm whale (Physeter catodon), with a head occupying one-third of its entire body.
Its teeth are usually broad, but many are narrow and pointed to catch squid. In the case of orcas, the teeth are very pointed to catch fish and other prey, such as sea mammals and sea birds.
The mouth or “maw” of the sperm whale has been the source of legend and at times terror as depicted in Melville’s Moby-Dick by way of the opening lines of Father Mapple’s sermon: The ribs and terrors in the whale,
Arched over me a dismal gloom, While all God’s sun-lit waves rolled by,
And lift me deepening down to doom. I saw the opening maw of hell, With endless pains and sorrows there; Which none but they that feel can tell Oh, I was plunging to despair.
The sperm whale’s mouth has a long and slender lower jaw or mandible, consisting of two halves that are wide at the joint surfaces (condyles),
where it articulates with the base of the skull and fused anteriorly to form an elongated chin or symphysis.
This appendage can approach six meters in length. Embedded in this mandible are two rows of broad, conical, and slightly recurved teeth angled towards the gullet.
And now behold Jonah taken up as an anchor and dropped into the sea; when instantly an oily calmness floatsout from the east,
and the sea is still, as Jonah carries down the gale with him, leaving smooth water behind.
He goes down in the whirling heart of such a masterless commotion that he scarce heeds the moment when he drops seething inro the yawning jaws awaiting him; and the whale shoots-ro all his ivory teeth, like so many white bolts, upon his prison.
Then Jonah prayed unto the Lord out of the fish’s belly. -Moby-Dick, “The Sermon” Melville’s metaphoric “white bolts” are firmly attached to, and largely covered by,
the fibrous dense gum tissue (gingiva) with only the tips of the teeth exposed to the elements.
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