National Geographic

The Brain-Chilling, Shrimp-Caressing, Lamppost-Sized, NSFW Organ Hiding In A Whale’s Mouth

This is a story about the discovery of an organ that measures twelve feet long and four inches wide. You might well assume that this is old news. After all, how could something the size of a lamppost go unnoticed by anatomists? And yet, in fact, it’s only just come to light.

The discovery emerged out of a blood-drenched confusion. Alexander Werth, an anatomist, was standing on an ice sheet miles off the coast of Alaska’s North Slope. He was watching Inupiat whale hunters dismember bowhead whales they had caught in the Bering Sea. This government-sanctioned hunt is one of the best opportunities for whale anatomists to get hold of fresh tissue from the animals.

Alex Werth in the middle of flensing a bowhead whale on the ice off of Alaska

Alex Werth in the middle of flensing a bowhead whale on the ice off of Alaska

To take apart the head of a whale, the hunters would slice off the lower jaws and the tongue, which could be as big as a minivan. They would then climb onto the roof of the whale’s mouth and cut away the baleen–the hair-like growths that the whale used in life to filter small animals from the water. On the roof of the mouths of bowhead whales, Werth and his colleagues noticed something strange: a peculiar rod-like organ stretching down the midline of the palate.

It had never been described in the bowhead before. What made the organ particularly peculiar was that, as the Inupiat cut the whales apart, it poured forth huge amounts of blood. Why, the scientists wondered, should a bowhead whale have an organ in the roof of their mouth? And why should it be so bloody?

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The roof of a bowhead whale’s mouth. The fur-like growth is baleen. The pink strip is a newly discovered organ. Photo by Craig George

One of Werth’s colleagues, Thomas Ford of Ocean Alliance, had noticed something similar in right whales twenty years ago. So Werth, Ford, and Craig George the Department of Wildlife Management at the North Slope Borough in Alaska decided to take a close look at the bowhead whales. They dissected some of the organs out of freshly killed whales, photographing them as they cut the tissue free. They brought one of the organs back to their lab, along with sections they chopped out of other organs, to examine under a microscope.

And this is where the story gets a little NSWF.

You see, the organ in the whale’s mouth turned out to be, biomechanically speaking, a twelve-foot-long penis.

Penises–in humans, whales, and other mammals–are made of a distinctively sponge-like tissue. When blood pours into the penis, the tissue stores it in a multitude of cavities, stretching out to hold the increased volume. As the penis swells, collagen fibers wrapped around the spongy tissue stretch and then tighten. Thus the penis becomes both enlarged and hardened. Unlike a bone, which is always hard, the penis can become soft again when its vessels pump out all the blood.

The organ in the bowhead whale mouth, Werth and his colleagues found, has the same distinctively spongy tissue, along with copious vessels supplying it with blood. Its anatomy strongly suggests that the whales can engorge it–hence the bloody mess it made when the whales were cut apart. Werth and his colleagues traced the blood vessels out of the organ and into the interior of the whale head. They found that they made close contact with a web of blood vessels at the base of the brain.

A diagram showing the location of the brain-cooling, food-sensing organ (marked "palatal CCM organ"). The front of the whale head is at the top, the brain at the bottom. From Ford et al 2013.

A diagram showing the location of the brain-cooling, food-sensing organ (marked “palatal CCM organ”). The front of the whale head is at the top; the brain is at the bottom. From Ford et al 2013.

Based on these findings and others, Werth and his colleagues think they know what the organ–which they dubbed the Corpus Cavernosum Maxillaris–is for. It has two jobs, the first of which is to keep the whale’s brain cool.

Staying cool may seem like the last thing a bowhead whale needs to worry about. Water is very good at pulling heat out of a body, even at lukewarm temperatures. And bowhead whales lead extraordinarily frigid lives, spending much of the year in the Arctic Ocean. You’d think that bowheads would need special adaptations to keep their warmth in, not to get rid of it.

Indeed, bowheads, like other marine mammals, have a very good adaptation for that job: namely, blubber. Bowheads are blubber champions, growing layers that can get as thick as 40 centimeters. The shape of their bodies also helps keep them warm;  Werth calls them “chubby, rotund zeppelins.” Their round shape gives them a low ratio of surface area to body volume. As a result, they can store more heat in their body and lose less of it through their skin than a thinner whale.

Unfortunately, solutions to biological problems have a way of causing problems of their own. As warm-blooded animals, bowhead whales generate heat, and when they’re foraging for food or migrating across an ocean, their muscles generate even more heat. Thanks to their anatomy, the whales are so well protected against the cold that this extra heat has nowhere to go. Too much heat can damage a mammal’s organs, with the brain being especially sensitive to even the slightest fluctuations of temperature.

Many marine mammals have adaptations to reduce this danger. A number of whale species, for example, have an intricate system of blood vessels that deliver hot blood from the core of their body into the dorsal fin on their back, where the heat can escape through the skin. The flukes of their tails and their fins can also dump heat. The whales can expand the vessels to release more heat when needed and constrict them to avoid losing too much.

Bowheads don’t have any dorsal fin at all, and the fins on their sides are small. So they swim very close to the thermoregulatory line. Werth thinks the Corpus Cavernosum Maxillaris keeps them from crossing that line.

The whales, Werth argues, fill the Corpus Cavernosum Maxillaris with some of the hot blood swirling around their heads. When they open their mouth, a colossal amount of chilly Arctic water pours in. The heat from the Corpus Cavernosum Maxillaris gets sucked away, cooling the blood. The cooled blood then travels back into the whale’s body. Because the Corpus Cavernosum Maxillaris contacts the base of the brain, it may be especially helpful for keeping the brain cool. The penis-like tissue it’s made of may allow the bowhead whales to switch off this heat dump by pinching off the blood vessels to the Corpus Cavernosum Maxillaris.

Heat escapes from the mouth of a dead bowhead whale. From Ford et al 2013

Heat escapes from the mouth of a dead bowhead whale. From Ford et al 2013

In a paper to be published in The Anatomical Record, Werth and his colleagues offer the details of their research that supports this theory. Here, for example, is a picture showing the mouth of a bowhead that was killed seven hours earlier. The bright colors show where it’s hot. The scientists found that the Corpus Cavernosum Maxillaris was still about twelve degrees hotter than the surrounding tissue. That’s the sort of intense heat you’d expect from a structure that had evolved to keep a whale cool.

This would be fascinating enough, but Werth and his colleagues suspect that the Corpus Cavernosum Maxillaris has a second job to fulfill. As they dissected the organ, they discovered that it is packed with nerve endings. What’s more, they have the shape and arrangement that makes them very sensitive to touch. In addition to dumping heat, the Corpus Cavernosum Maxillaris may be a sense organ. Werth proposes that these nerve endings in the Corpus Cavernosum Maxillaris help bowhead whales eat.

Baleen has enabled some whale species to become gigantic. The blue whale, in fact, is the largest animal to have ever existed. But using baleen to feed is no simple matter, and scientists are just starting to appreciate the complexity of the choreography it demands. Fin whales, for example, drop their jaws and let the skin balloon out like a parachute, engulfing a volume of water about equal to a school bus. They then swing their jaws shut and push their enormous tongue forward, squeezing the water through their baleen. Each gulp can yield a fin whale half a million calories. (See my pieces in the New York Times and the Loom, plus Ed Yong’s piece for more details.)

Bowhead mouth closed (top) and open for feeding. (Werth 2004 http://jeb.biologists.org/content/207/20/3569.full )

Bowhead mouth closed (top) and open for feeding. (Werth 2004 http://jeb.biologists.org/content/207/20/3569.full )

Bowhead whales use a different strategy that’s no less demanding. They open their mouths partway as they swim, ramming water through mouth and letting it spill out the corners. Animals get trapped in the baleen along the way.  Bowhead whales can ram three cubic meters of water each second. While that’s a good way to capture a lot of food, it also demands a huge amount of energy. If a bowhead rams water with few animals in it, it ends up losing more calories than it gains.

It might be very useful to such an animal to know how much food is in the water it’s taking in. An exquisitely sensitive organ in the roof of their mouth might be just the thing a bowhead needs, telling it whether it can enjoy a banquet in its baleen or needs to shut its mouth and find better hunting grounds.

Bowhead ram feeding (Werth 2004 http://jeb.biologists.org/content/207/20/3569/ )

Bowhead ram feeding (Werth 2004 http://jeb.biologists.org/content/207/20/3569/ )

I asked Jeremy Goldbogen, an expert on whale feeding at the Cascadia Research Collective, for his opinion on the new paper. “What a fascinating and exciting study!” he wrote back in an email, endorsing Werth’s idea that the Corpus Cavernosum Maxillaris has two jobs to perform. This means a lot coming from Goldbogen. He was part of a team that also discovered a gigantic sensory organ in fin whale jaws; those whales probably use it to control their gulps. (See this post by Ed Yong for details.)

The work of scientists like Werth and Goldbogen makes clear that there are enormous mysteries left for anatomists to solve. And if Werth and his colleagues are right, scientists may rethink many aspects of bowhead life. Opening their mouths may not just be a way for the whales to catch food. It may also be a way to stay cool. And it may be no coincidence that on their long migrations between the Arctic Ocean to the Bering Sea, bowheads are sometimes seen with their mouths gaped open. Like a panting dog, they may be trying to stay cool among the icebergs.

Painting by Carl Buell

Painting by Carl Buell

[Thanks to Carl Buell for his paintings. Visit his Facebook page for more natural history goodness.]

[Update: changed muscle fibers to collagen fibers. Thanks to Diane Kelly for pointing that out.]

There are 24 Comments. Add Yours.

  1. Gaddy Bergmann
    March 4, 2013

    Such a fascinating story!

  2. Jeff Holton
    March 4, 2013

    Oh, parts of this article make D.H. Lawrence all the more relevant!

    c.f., “Whales Weep Not,” specifically, “the hottest blood of all, and the wildest, the most urgent.”

    The burning archangels under the sea keep passing…

  3. Melissa Koski
    March 4, 2013

    What an amazing discovery!

  4. David B. Benson
    March 5, 2013

    “What a fascinating and exciting study!”

  5. Jon Summers
    March 5, 2013

    I note wryly that despite the huge expense of the Japanese ‘scientific’ whaling industry, the Japanese are more interested in how whale tastes than how whales taste.

  6. dru-quan
    March 5, 2013

    this is crazy and is a crazy story

  7. judy foremanC
    March 5, 2013

    Can’t resist the obvious: That’s a whale of a story!

  8. cy kennen
    March 5, 2013

    In response to the japanese whaling comment, I’ve heard it described as tasting like beef that was raised on oily sardines. But eaten raw. And possibly 100 years or more old! Sounds delicious. What kinds of parasites does one find in decades-old sea mammal flesh?

  9. Karl
    March 5, 2013

    This is a fantastic blog, but why do you use feet and inches and not meters and centimeters? Its so medieval with feets and so unscientific.

  10. Anita
    March 5, 2013

    Had this centuries old tradition been denied the interesting Inupiat, would we ever have known? There is much anew in teh old………

  11. Bob
    March 5, 2013

    This story made me sad. I’m sure the Inuit already had a name for the piece they cut out yet it’s given a latin name. Inuit people (and others before them) have been cutting that piece out for thousands of years but it only existed after a white person saw it. He renamed it and claimed it as his “discovery.” When I read stories like this I often wonder what the original name was of many things across the earth.

  12. junardin
    March 6, 2013

    i think its a very peculiar study… how can a penis be situated in the mouth of a mammal. for sure whales do have weird sexual activities

  13. Ralph Dratman
    March 6, 2013

    I must admit that the idea of any animal struggling to stay cool while completely submerged in icy salt water seems hard to, um, swallow. Are there any figures available on the volume, surface area and heat production of these whales? Naturally, just opening their mouth would expose a lot of additional area for heat exchange. If the heat theory is correct, these creatures are continuously warming up the ocean for their whole lifetimes! One of us, in their situation, could warm up the ocean, by an almost undetectable amount, for maybe a total of five minutes. Then we too would become icy salt water.

  14. john
    March 6, 2013

    tom ford is a genius

  15. Lauren Murphy
    March 6, 2013

    Wow, that’s an incredible find considering whale anatomy has been documented for centuries. The functions sound valid to me and the article was incredibly fascinating!

  16. Bill Shear
    March 6, 2013

    I’m very delighted to see my departmental colleague, Alex Werth, getting the notice his fantastic research deserves. We both teach at a small college of 1000 students (Hampden-Sydney College), and Alex is constantly demonstrating that one can still do top-notch research and publish at a small liberal arts college with a pretty heavy teaching load. It can be done!

  17. Nancy
    March 6, 2013

    Is it true that scientists think bowhead whales can live for over 200 years?

  18. Marcus Pendergrass
    March 6, 2013

    Fascinating. I wonder if Werth and colleagues think that the copius nerve ending in the Corpus Cavernosum Maxillaris might be able to sense taste?

  19. Tork
    March 6, 2013

    “What kinds of parasites does one find in decades-old sea mammal flesh?”

    I don’t know about the parasites, but according to a study done at Hokkaido Uni. a few years back, one does find shockingly high levels of mercury.

  20. Barbara
    March 7, 2013

    Although the problem is a lot less extreme than for Bowhead Whales, Pied-billed Grebes also have times when they must dissipate heat although they’re equipped to keep warm in cold water. Grebes, who can barely walk,* spend nearly all their lives in or on the water, even nesting in wet floating nests.** Therefore, they must be well insulated. The chest and belly are covered with lustrous feathers almost as dense as those of penguins. (This part of their skins was once used to make muffs to keep human hands warm.) When their amazingly flattened feet aren’t needed for swimming, the feet are tucked away along the birds’ sides, between the dense chest feathers and the looser back feathers, under the wings. Once the bird tucks its head under its wings, it becomes a compact feathered oval, warm even in icy water. But what happens in warm ponds on hot days?

    Like most birds, these grebes have feathers distributed in bands called feather tracts, with featherless areas between. (The “featherless” area may have down feathers.) The featherless area beneath the grebes’ wings, in their armpits, are large and adapted for heat exchange. These are the surfaces where grebes brood their chicks.*** This is also where grebes can place their cold toes to warm up.

    On hot days with little wind, hot Pied-billed Grebes that have been foraging bathe, getting their bare armpits wet. (Their chest and belly skin can’t get wet; those dense lustrous feathers form an essentially waterproof barrier.) Then the grebes “wing-shuffle.” They lift one folded wing up an inch or so, then bring it down and the other one up. Repeat, repeat, fast. This moves air over the bare armpits, cooling the grebes down.

    * (although they can precariously run if placed on a smooth floor, until they trip over their own toes)

    ** (Pied-billed Grebes can fly, of course, with all the desperate grace of overloaded bumblebees. Two of the three I ever saw in flight crash landed in the water, one while sideslipping to loose altitude just after I, and presumably it, realized that its trajectory was going to cause it to crash into the levee.)

    *** (Think about it; if these aquatic birds with their wet floating nests brooded by sitting on their chicks, they’d drown them. Instead the little grebe babies ride on their parents’ back, warm under the wings, sometimes sticking a head out to watch the world go by.)

    Reference: Wilson, Barbara L. 1982. Wing-shiffling as a thermoregulatory mechanism in the Pied-billed Grebe (Podylymbus podiceps). Unpublished Masters Thesis, University of Nebraska at Omaha.

  21. Steve Savage
    March 7, 2013

    Hats off to Craig George! Over 30 years of research on the Bowhead whale, including the startling find of ancient spear tips that allowed him to discern the longevity of this remarkable animal.

  22. Krish
    March 11, 2013

    Can anyone expand NSWF? or is it NSFW?

    Thanks

  23. Michael Owen Sartin
    March 11, 2013

    Krish, NSFW = Not Safe For Work or Not Suitable For Work.

  24. Briscoe
    September 23, 2013

    Lived in the articl for years. Why do the white scientists refuse to acknowledge the accumulated knowledge of the people who have lived and hunted for centuries? Do they not know how late in the day they are? I commend them as well as find them embarrassingly ignorant of ancient knowledge. Not all scientists who come here are this way. When cultures cooperate with mutual respect amazing things happen

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