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Great white shark, seen here off the coast of South Africa. Photo: © 2013 Travelbag Ltd. Licensed under Creative Commons Attribution License.

Nine-Foot Great White Shark Eaten by Unknown Sea Creature

Gizmodo’s James Baker highlights Smithsonian‘s story of a tagged nine-foot (2.7m) great white shark whose electronic tag washed up on the beach. When scientists checked the data, they discovered a terrifying sequence of events: the tag had been dragged 1,900 feet (580m) below the surface, then eaten—achieving a 78°F temperature. So this raises a reasonable question: what could possibly eat a nine-foot great white shark?

Conventional wisdom would suggest that it was an orca, obliviously gobbling up the tag while foraging for shark livers. They’re large enough—typically two to three times the size of the missing shark—and they have a well-documented history of hunting great white sharks. But the trouble with this theory is that as far as we know, orcas never go that deep; they typically stay near the surface, with the deepest recorded dive measuring 850 feet (259m) under controlled conditions. So if this was an orca, we have a new record. (EDIT: An orca’s internal temperature typically runs to 97°F-100°F, so we’d also have a very cold orca.)

Another possibility, raised by several Gizmodo commenters, is that the shark itself was attacked or killed near the surface of the water, dislodging the tag, which was then separated from the shark, dragged underwater, and eaten. The problem with this theory is that great white sharks are lamnoid sharks, which means that their body temperature tends to run slightly warmer than the surrounding water. If the tag and/or surrounding tissue had been removed from the shark before it was consumed, the tag would have presumably recorded an abrupt temperature drop prior to the temperature increase. It didn’t. Something dragged the nine-foot, still-living shark more than a third of a mile underwater, then ate the tag.

Could another great white shark have done it, as the documentary suggests? Possibly, but I don’t see how; assuming the tag was lodged in muscle tissue… (It wasn’t.) The temperature range of a great white shark’s belly under these circumstances would be 13-25°F warmer than the surrounding water temperature, somewhere between 52°F 59°F and 64°F 71°F. The temperature recorded in whatever it was that ate the shark was a fairly steady 78°F.

Any ideas, readers?

(EDIT: I’ve written a followup post that may be of interest. -TH)

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  • SunnyInAlaska

    Actually, sperm whales are known to eat other species of sharks as well as colossal squid which are much larger than the 9 foot great white who got eaten. Per http://www.nwf.org/Wildlife/…/Sperm-Whale.asp

    “The sperm whale prefers ice-free waters at least 3,300 feet deep. When hunting squid, a whale may dive in excess of 6,500 feet–more than a mile–and can stay under for more than an hour.”

    A sperm whale is large enough, hunts up-side-down beneath its prey and surprises them from below, can dive that deep and swims as fast as a great-white’s top speed. The question is whether the internal temperature would be consistent with whatever ate the shark.

    Also, it’s quite possible that something attacked the shark and the tag got ripped off in a chunk of fin which was then eaten by something else.

  • SunnyInAlaska

    Ok, sperm whale body temperature is between 33-37 degrees Celsius (91-98 degree F). They do cool their head temperature to only 2 degrees C (less than 40 degrees F) to solidify the oil in their skull into wax. Makes them heavy so they can dive faster. However, their body temp stays high so that they can turn the blood supply back on in their head when they want to ascend again. So, their stomach is a long way from their head.

  • Donald Bellunduno

    Actually, they can kill great whites. If going fast enough, and they can echo locate lunch
    Easily enough. A NOAA scientist confirmed this for me.

  • reswire

    Sasquatch in scuba gear!! What else could it be?

  • Nathan Tieche

    well to be far there is something like 90% of the oceans still unexplored