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MythBusters Episode 102: Shark Week Special 2

Air Date: July 27, 2008

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In shark-infested waters, a person can reduce the their chance being attacked by playing dead.

confirmed

To test this myth, the Mythbusters traveled to the Bahamas and attracted several sharks by chumming the ocean water. Tory and Grant then donned protective chain mail and entered the water, floating a short distance from each other. The two took turns thrashing about and playing dead. Each time, the sharks were clearly more attracted to the person who was actively thrashing.

(This myth was based on real stories of survival from Navy sailors aboard the USS Indianapolis in 1945. The cruiser was torpedoed near the Philippines, stranding some 900 sailors in the water for 4 days. Of the 317 men who survived, several attributed their survival to playing dead when sharks were near.)

In the frenzy of a shark attack, a person can successfully find and gouge the shark’s eyes in an attempt to repel it.

plausible

Adam and Jamie built a life-sized fiberglass shark for this myth. The shark had an articulating body to simulating thrashing and pneumatic jaws with 90 serrated, removable steel teeth. It also featured eyes made of rubber buttons, which shut the shark off when pressed. As a test subject, they used Tory, who knew the shark could be shut off, but he supposedly did not know how. It took Tory about 15 seconds of thrashing in the shark’s jaws to shut the shark off. Adam also got in the jaws, upside down, and struggled to reach the eyes. The team called this myth “plausible”, noting that a person’s success with this method of defense would depend on the particular circumstances of the attack.

During a nighttime dive, flashlights will attract sharks.

confirmed

This myth is based on the idea that the electromagnetic field created by flashlights may attract sharks. The Mythbusters first performed a control dive to see how many sharks appeared at night when they dove without flashlights. When they tried diving with flashlights, significantly more sharks appeared in a shorter amount of time and the sharks behaved more aggressively toward the flashlights.

Magnets are effective for repelling sharks.

busted

This myth is based on the fact that sharks have sensory organs called ampullae of Lorenzini, which are capable of detecting electro-magnetic fields. The Mythbusters tried several experiments to test the deterrent power of magnets. First they used a young, captive nurse shark. A handler immobilized the shark by turning it upside down. Jamie then brought a magnet near the shark, and it bent away from the magnet. When the shark was upright, it bent away strongly and tried to escape from the handler. The Mythbusters also used a sheet of plastic to hide the approaching magnet from the shark’s vision. In this condition, the shark tried to bite at the magnet through the opaque sheet when the magnet was brought near. Next, another nurse shark was used for a different test. The shark was in a small pen, and the a row of magnets was used to divide the pen in half. The shark would not swim over the magnets, but it would swim over a line of steel chunks used as a control. Finally, the Mythbusters covered fish-filled bait boxes with strong neodymium magnets and submerged them in waters infested with wild, adult lemon sharks. These sharks attacked the boxes aggressively regardless of whether there were magnets on them. This myth was declared “busted” because the magnets did not work for all species of sharks nor when there was food present.

Chili peppers are an effective shark repellent.

busted

Adam and Jamie puréed dozens of habanero chilies and used the resulting paste to fill balloons. These balloons were attached to bait boxes and were submerged in the ocean. Adam was planning to pop the balloons with a pneumatic needle but the sharks took the initiative and attacked the balloons. The sharks that bit the balloons did not show any sign of discomfort or repulsion, and the other sharks and fish swimming through the cloud of chilies were not repelled.

The chaotic paddling and the scent of a dog will attract sharks.

busted

The build team created a robotic dog complete with fur, barking speakers, and paddling legs. The dog was also equipped with syringes that could deploy dog urine, dog blood, and dog anal gland secretion. None of these elements attracted any sharks.

Mini-Myth: Sharks can see and will attack food that is above the surface of the water.

confirmed

The Mythbusters attached shark bait to the end of a stick and held the bait a few feet above the water. The sharks repeatedly emerged from the water and took the bait.

(This mini-myth was based on a seen from the movie Deep Blue Sea in which shark jumps out of water and catches a pet parrot.)

There are more shark myths in the JAWS Special.

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25 Comments

  1. Ted Steedman:

    While watching the show tonight, I was struck by Grant’s obvious fear (of water, sharks and whatever else). I had two thoughts: 1) Why is Grant doing this when he is so afraid? and 2) Kudos to Grant for going ahead and participating; his actions were an inspiration to many! Thank you!!

    July 27, 2008 at 10:58 PM
  2. John M:

    I don’t think it’s so much playing dead as keeping still. Not acting like a fish.

    July 28, 2008 at 11:33 AM
  3. P:

    On the flashlight attracts sharks myth, it was Plausible, not Confirmed, because the crew didn’t know if the sharks were attracted to the light because of the electromagnetic field or if they were attracted because of the unusual amount of light.

    July 28, 2008 at 1:31 PM
  4. P:

    My explanation might not be totally right, but I know for sure that they said it was Plausible. They air the episode next time on Wednesday night 8:00 PM (Central time).
    They decide the “verdict” of this myth(flashlight attracts sharks) in the last 30 minutes of the show.

    July 28, 2008 at 1:43 PM
  5. raysmash:

    right after i watched mythbusters i watched survivorman. some of his shark tests proved to be very diferent. the sharks you tested in is it safer to play dead or thrash react diffrently than tigersharks and great whites to than “myth” im also dissapionted that great whites werent actually tested since you were busting myths about a great white. the same sharks you tested at night he also tested at night. the sharks wouldnt even eat chum becouse of the divelights were blinding them. i love the mythbusters show but i think you should watch survivormans sharkweek special he tested nearly the same myths and had more convincing results.

    August 3, 2008 at 8:39 AM
  6. E:

    P, you are right. it was considered plausible by Mythbusters, NOT confirmed.

    but after watching that one i was a bit irked. they said the attraction of the sharks could be attributed to the illumination of prey, the electromagnetic fields, yada yada yada. what bothered me is THATS WHAT FLASHLIGHTS ARE SUPPOSE TO DO. it SHOULD have been confirmed. they werent trying to figure out what about the flashlights attracted sharks, just IF flashlights attracted sharks. and they obviously did.

    August 3, 2008 at 5:50 PM
  7. Diddy:

    Great info, I love this show!

    August 5, 2008 at 9:17 PM
  8. Tim:

    Interestingly, during shark week, the Survivorman special sort of explored the “playing dead” myth, and got a different result. They found that a moving person was less likely to be bitten than a still person (who was floating horizontally).

    August 13, 2008 at 6:52 AM
  9. Fahry:

    It’s me again, i think it’s is kinda cool taht you did some shark myths, but you forgot one myth, Sharks are blind and the only way it can find food is by smell blood leaking out of an injured prey.

    August 15, 2008 at 8:38 PM
  10. Bob:

    Where did you get the idea that sharks are blind? They actually have very good eyesight, including the ability to discriminate color. See, for example:

    http://www.enchantedlearning.com/subjects/sharks/anatomy/Senses.shtml

    August 18, 2008 at 12:04 AM
  11. H:

    You guys should tackle bigfoot, nessy, and the like.

    August 18, 2008 at 12:44 PM
  12. dehron:

    can heat really burn a hole trow your body

    August 30, 2008 at 1:44 PM
  13. Dennis:

    Can somebody jump off of a house and land safely in a pool?

    September 4, 2008 at 6:49 AM
  14. Fahry:

    I must say,what is the the difference of playing dead and staying still. And also, your chances of being attacked are higher if you swimlike crazy and make loud noises.

    September 5, 2008 at 8:02 PM
  15. joel:

    hey i really like your show and i have another myth for you, i was watching lethal weapon 2 and in the movie mel gibson took his 6 wheeler truck , hooked a chain to the support beams under the building and pulled the beam from its concrete support, and destroyed the building, is that possible, you tell me and try it out

    September 21, 2008 at 8:28 AM
  16. Jacob Diaz:

    can a person really escape from a shark by punching it in the nose.

    September 26, 2008 at 9:08 PM
  17. josh stephens:

    hey adam you now wen you took out the vocume and the moter got your face that was funey.

    December 4, 2008 at 10:18 AM
  18. josh:

    this is about a compleatly diferant myth home made fly repelent what can you use if you are out of comercial fly repelent

    March 19, 2009 at 4:51 AM
  19. Garry:

    Hey Guys, Im From Australia and we play around with sharks fishing a fair bit now i can say 1-3 things about sharks tiger great white’s even bull sharks, some times sharks bite things because they are just Curious EG: if your in fluro yellow comapred To being say in a blue suit they have neer seen Yellow so they bite to lets say have a feel of what your are and if you are a source of food, Tiger sharks will pretty much eat most things that come in their path Inc Numberplates tins Children small dogs ect, Great whites love to hunt prey that looks like seals or any other fav creature so they might even be Curious as to what the light is at night time so much they come have a look or if they are really curious will have a bite im not saying they will and wont Because they simply DO BOTH!!!!! its just what apeals to them now lets say there is 10 of you in the water 7 of you are splashing about another 3 play dead then of course the obvious is the splashing is Distress = food source feel free to experiment with a Kitten at home get 2 people one does a slow movement of hand while the other is quicker and see which one it goes after not moveing = boreing / movement = Curiosity there for will stalk the moveing its predatory instinct but as i say easy can be the option aswell just thought on the subject i’d thought i’d add my 5 cents on the subject :) im neither right or wrong

    April 2, 2009 at 7:53 AM
  20. Sweetwater Tom:

    Wired magazine just had an article on magnets and sharks. It will add some fuel to this fire.

    Garry – Thanks for your note. It seems that many shark attacks on surfers are a single bite. Apparently the shark thinks the surfer is an otter, seal, or other delicious morsel and when it tastes something different it goes away. Not sure if it is the surfer or surf board that tastes so bad. :)

    Tom

    May 16, 2009 at 7:29 AM
  21. Karen:

    I just wanted to say that I love this show! Last year on July 27, 2008 I gave birth to my first son, during the labor the doctor, the nurses, my husband, and I all watched the show. In between my contractions we would all watch this episode and make comments, and then during contractions I would focus on the show. It helped me during the hard parts and I want to say THANKS! I love this show!

    May 23, 2009 at 10:36 AM
  22. Bubbles:

    I wish they had tested with a big electromagnetic transducer inside the feeding box, and maybe try to run it at different frequencies. A large time-dependent field should be much more unnatural for them. Should probably also be tested in an otherwise empty box, to make sure they don’t get curious at the device itself. :)

    August 23, 2009 at 3:46 PM
  23. Marty:

    In Aussie land now there is alot of people who swear by a product called “Shark Shield”. It emits an electric pulse into the water.

    Some people (including a top female surfer) also swear by colours that make the surfboard look stipey black & white like a lionfish or sea snakes.

    September 19, 2009 at 2:10 AM
  24. String:

    The dog myth was totally bogus! That robot dog sucked! Real dogs thrash around in the water. Their robot thrashed around about as much as a turtle. Do over!

    November 26, 2009 at 7:33 PM
  25. J:

    I agree about the whole dog myth. Even though they can’t use an actual dog to conduct the experiment, the movement of the dog was sluggish and slow and so fake. Unlike real dogs who actually dog paddle. I’m surprised the blood didn’t the sharks nuts. Or the urine. Sharks apparently can’t be fooled that easy.

    November 28, 2009 at 4:33 PM

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