What is it like to be a whale?

January 7, 2012 • 9:53 am

ScienceNow has a short but intriguing piece by Elizabeth Pennisi called “A whale’s virtual reality.” It summarizes results presented by Jeremy Goldbagen and his colleagues on some baleen whales that feed on “bait balls”: groups of fish or krill (shrimplike marine crustaceans).  The whales lunge toward the balls, opening their mouths and ingesting huge amounts of water along with the prey. Then they expel the water through their baleen plates (extensions of the mouth’s mucus membranes).

Whales were tagged with radio transmitters affixed to the beasts with suction cups.  Pennisi reports the pretty amazing findings:

The work showed that in one giant gulp, a blue whale—the biggest creature on Earth—takes in 125% of its body weight in water and krill. During their dives, the cetaceans ram into patches of krill, opening their mouths wide and wrapping their jaws around prey-laden water, a move that stops them short. Next, they close their mouths and push water through their baleen, a system of plates that filter out the food, then speed up for another feeding bout.

But details about this feeding strategy had been lacking. This past summer, Goldbogen monitored several blue and fin whales with new tag technology that detects the changes in the whales’ orientation in space, much like smart phones “know” whether they’re held in a horizontal or vertical position and adapt screens accordingly. For the 6 to 24 hours they are attached to the whale, the tags also record depth and sound; from the loudness of the water rushing past a diving whale, researchers can calculate its speed. “We use these sensors to reconstruct what the whales are doing,” Goldbogen said.

The new tags show that as they gulp, the whales often twirl around like a corkscrew with surprising agility, Goldbogen reported at the meeting. They also will lunge from all different angles, not just horizontally, as previously thought. “We see these amazing maneuvers,” Goldbogen said.

125% of its weight in water and prey!!

Here’s a computer animation based on the tracking data from a single blue whale:

[vodpod id=ExternalVideo.1009927&w=425&h=350&fv=]

In the video [above], a tagged blue whale dives twice over the course of 19 minutes. The movie shows the whale moving at about 50 times its cruising speed. The first dive, to about 15 meters, takes about 2.5 minutes in real life; the second one, which includes feeding bouts, lasts more than 12 minutes and reaches down to 180 meters, where the whale lunges five times in quick succession, as if it were on a roller coaster.

This is not a great video, but it’s the best I’ve found on YouTube to show the feeding behavior. In the first ten seconds, you see the whale twist its body and open that huge mouth to ingest a group of krill. It’s pretty amazing that the largest animal on earth sustains itself with tiny invertebrates.

h/t Aidan

26 thoughts on “What is it like to be a whale?

  1. Cave crickets (Hadenoecus subterraneus) regularly consume >150% of their own body weight during one of their nocturnal foraging bouts.

  2. “It’s pretty amazing that the largest animal on earth sustains itself with tiny invertebrates.”

    And the whale shark does the same. Must be surprisingly good eating for huge animals.

  3. “125% of its weight in water and prey!!”

    Can this really be right? Assuming neutral buoyancy, it implies that just by opening its mouth, the whale more than doubles its volume — that there’s room enough inside that open mouth for another whole whale.

    1. I bet no one has actually *weighed* one of the damn things when it’s eating! Huh – smartass scientists!

      1. I bet no one has actually *weighed* one of the damn things when it’s eating!

        Stick an accelerometer onto the beast ; you can measure how fast the beast can accelerate itself forwards by strokes of it’s flukes ; you can measure how fast the the animal decelerates itself by “engulfment feeding”. Those accelerations require energy for each unit of mass. Once your eyes have stopped watering, you can try to work out how much energy the animal can get by combustion using one (or several ; do your whale biology) lungs full of (21% O2) air. The kinetic energy for the accelerations can’t be (much) greater than that delivered by the lung-limited metabolism. That should give you enough constraints to work out the mass with a moderate degree of accuracy.
        (Or you could just read ‘Moby Dick’ or other whaling records. Melville knew the whaling industry and was a reasonably reliable observer.)

        Huh – smartass scientists!

        Indeed they are. I’m (moderately) surprised that nobody thought to work out the energetics of whale feeding before the last couple of decades, when the matter ought to have been a fundamental interest of a whale “fishery” for around a century. Then again, none of the fishing industries have an exactly stellar record of understanding their industry’s basic science in the way that agriculture went through a science-based revolution in the 16th and 17th centuries (and more since). And boy do the fishing industries not like to be told “if you catch the immature fish, soon you won’t catch any fish”!

        1. Ditto for “if you catch fish faster than they can reproduce, soon you won’t catch any more fish.”

          Funny how, even with all the problems that we have seen and all the places where bad behavior has caused permanent damage, people still don’t want to bother trying to do something different.

          Nope, you try to point out that someone is doing something that’s going to result in the destruction of their livelyhood, they accuse you of caring more about fish/whales/birds/fungi instead of jobs even though you’re actually trying to insure that there will continue to be jobs.

    2. That depends on what the density of the whale is.

      I’d imagine that their density is actually fairly low, given how much of their body mass is made up of blubber.

      1. If their average density were much less than that of water, it would cost them energy to stay submerged. This is why fish have swim bladders: to adjust their internal density to maintain neutral buoyancy. I assume whales have some similar adaptation, and I’m guessing part of the function of blubber is to offset the high density of the bones. So a density near that of water seems a reasonable assumption.

        1. I don’t know about the Rorquals, but the Southern Right Whale supposedly floated after it was killed, which was one of the reasons it was such a popular target for whalers.

    3. Well, the grooves on the whale’s throats allow an IMMENSE expansion of that gigantic mouth.

      It sounds hard to swallow (ba-dum-tsh), but I am willing to believe that figure is fairly accurate.

    4. As Asura points out, look at the grooves and pleats along the lower jaw of a rorqual whale : the volume they can engulf is huge. Also, the mandible can drop open to an angle of something like 90 degrees to the upper mandible (sorry – “dentary”? ; not quite up to speed on whale naming-of-parts) ; look at it as if it were an airbrake on a wing, that is approximately half the width of the wing, and that extends the whole length of the wing.
      Not that long ago I was reading similar results (possibly from the same team ; the techniques used were certainly similar) from doing inertial studies of the natural environment behaviour of rorqual (“baleen”) whales. The whales speed of motion was recorded across several dives by sticky-pad type sensors.
      100 tonnes of whale swimming at a good rate of knots in the sea has a certain amount of kinetic energy. When it stops finning (detectable by changes in the fine pattern of movement of the sensor), it does not stop immediately. That’s inertia for you.
      But when it opens it’s jaws, it slows in a couple of seconds to around half it’s previous speed.
      Given that the animal as a whole is well streamlined, this does imply that when it opens it’s mouth, it engulfs a volume of water comparable in mass to it’s entire body ; that mass of water is then accelerated to approach the velocity (NB : I know how to spell “speed” ; I typed “velocity” because that’s what I mean) of the whale before opening it’s mouth ; simultaneously, the body of the whale is negatively accelerated by a force applied to it’s lower jaw. That’s Mr Newton’s Third Law in action (brings tears to my eyes!). The two forces act on the elastic membrane that forms the pleated “pouch” depending from the whales lower jaw.
      That’s some serious forces acting on that jaw, that jawbone, and that “pouch”.
      I’ll see if I can find links to the papers …
      Didn’t take long : searching Google for “Goldbogen whale jaw force” I come up with http://ccom.unh.edu/vislab/PDFs/WareEtAl_HumpbackLunges.pdf “ABSTRACT
      Humpback whales (Megaptera novaeangliae) belong to the class of marine mammals known as rorquals that feed through extraordinarily energetic lunges during which they engulf large volumes of water equal to as much as 70% of their body mass.”
      http://www.cascadiaresearch.org/reports/Goldbogen%20et%20al.%202011%20J.%20Exp.%20Biol..pdf “Under this scenario, the engulfed water is gradually
      accelerated forward by virtue of action–reaction (Potvin et al., 2009),
      and a forward ‘push’ of the engulfed water mass gives rise to a
      novel source of hydrodynamic drag from inside the mouth
      (engulfment drag), in addition to the drag generated from flow
      around the body (shape drag). The combined drag acting on the
      whale’s body rapidly dissipates its kinetic energy, bringing the
      lunging whale to a near halt.”
      As I thought when I first encountered the subject, there is some pretty amazing stuff going on in those whales. Do you fancy doing your eating by running at full tilt into a hook that catches you by the bottom jaw and drags you to a halt? Then doing it another half-dozen times in a feeding run, before surfacing? Ouch!

  4. Odd, I’ve just tried posting a longish message, twice, and it’s not showing up. Aren’t I glad I save it to a text file first! I’ll see if it gets through the filters in a little bit, and if not, try doing it in parts.

  5. Consider that a body (animal or insect, for that matter) is a tube. The animal is primarily lined with skin on the outside adn mucosal membrane on the inside. Drain the gut (mouth to anus), and you have actual body weight. I don’t recall the equations, offhand, but the amount of material in a solid cylinder compared with the same amount in a hollow tube can leave quite the hollow, depending on how thick the wall of the tube, is. So, the whale-tube passes a sea-and-feed solid cylinder through. Impressive! Makes sense, but still, impressive!

    As for the tiny feed for the large whale, that just means the whale doesn’t have to chew to mechanically reduce its meal to a more digestible size. How efficient!

    Otherwise, the whale might require fewer feedings, longer time to digest between feedings, but more energy expenditure for digestion, itself. This would seem to add up to a slower metabolism and lower body temperature, so it wouldn’t require too much energy outside of digestion. The high energy for hunting and consuming, though, might then become a problem.

    Just guessing… Fun to do.

  6. “What is it like to be a whale?”

    In the 70’s I was working with a grad student at Cornell on certain Nymphalid butterflies. During that time, the department herpetologist gave a seminar entitled, “What it’s like to be a lizard.” Tom & I immediately decided we, then, should offer, “What it’s like to be a satyr and a nymph . . .”

    But I digress . . .

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