Episode 102: Shark Week Special 2

Air Date: July 27, 2008

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.

40 Comments

  1. Ted Steedman says:

    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!!

  2. John M says:

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

  3. P says:

    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.

  4. P says:

    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.

  5. raysmash says:

    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.

  6. E says:

    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.

  7. Diddy says:

    Great info, I love this show!

  8. Tim says:

    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).

  9. Fahry says:

    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.

  10. Bob says:

    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

    • MSpears says:

      He never said that sharks are blind. He said it’s a MYTH that sharks are blind. (Which it is.)

  11. H says:

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

  12. dehron says:

    can heat really burn a hole trow your body

  13. Dennis says:

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

  14. Fahry says:

    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.

  15. joel says:

    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

  16. Jacob Diaz says:

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

    • MSpears says:

      Maybe. It’s better to try to poke it in the eye, though. For one thing, it’s a more vulnerable (and more sensitive) target…

  17. josh stephens says:

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

  18. josh says:

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

  19. Garry says:

    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

  20. Sweetwater Tom says:

    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

    • MSpears says:

      *snickers* I can almost form a mental picture of a shark biting a human, making a funny face, and saying “YUCK! Human!”

  21. Karen says:

    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!

  22. Bubbles says:

    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. :)

  23. Marty says:

    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.

  24. String says:

    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!

  25. J says:

    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.

  26. nsurf says:

    neodymium magnets are strong, but have a small field of influence compared to iron ferrite magnets. Were both types used and if so, was there a variation on the different types?

  27. Max says:

    The iTunes version and recent airings of this episode cut out flapping fish, salsa shark repellant, and flashlight shark repellant. Secondly, it’s only an hour long.

  28. ekm says:

    mythbuster says playing dead will save your life and survivorman says swimming will save your life. i live on the gulf and am surrounded by sharks, so which is true or does anyone even know?

  29. Rob Australia says:

    Having just watched this i can see a major ‘flaw’ in their magnet test.

    First off if you watch the test, the ‘standard’ normal iron feris magnet on the pup had it pull away.. the Neodynium it had a go at the paper between.

    Then go to the test in the pen.. they used standard feris magnets.. and the pup wouldn’t cross them however rather then use those SAME magnets on the sea test.. instead they used the Neodynimum maginets again.

    I say go back and do tests with BOTH sets all along.

  30. art says:

    I would question the definition of “food”. I think the kind of chum used would stimulate the fish to the point that they would ignore anything short of physical restraint to get at the food. Sort of like the bull taking a run at the electric fence, it only hurts briefly and then you’re free. But it does seem to have potential for limiting shark movement under less dramatic circumstances. I believe some Australians are presently exploiting the magnet effect.

  31. felixnoir says:

    There was a recent report in the ‘West Australian’ newspaper about a swimmer who was mauled by a shark but escaped by eye gouging. I’ve seen other reports of people who have escaped shark attacks by attacking the shark. With ref to movement: I’ve seen an article somewhere that said sharks see some movement as ‘distressed’ and other movement as ‘aggressive’, which affects whether they will attack. The reason is other cues – scent, but apparently also subtle differences in the vibration of the water, which sharks are very sensitive to. This seems to me to make sense, because the ability to distinguish different reasons for violent movement would be an important evolutionary survival trait.
    With ref to what Sweetwater said: Tigers that eat humans apparently only do so because they are too old to catch harder prey. The reason is, humans taste awful. The taste of tobacco in human flesh is one thing that apparently really puts animals off.

  32. Randomdiver says:

    It seems everyone has missed one vital point here,i havent seen anyone mention it and it wasnt mentioned on the show (being repeated now on tv).
    Every fisherman knows (or should)when a fishes bite time is, when it’s at as its most active feeding and when its not.At these bite times i have seen even freshwater perch for e.g in a baitball type frenzy eating anything in site so i know the moon,tides etc all affect a fishes activity.
    Some of those tests might or might not have been done during these times which would def make a big difference in sharks activity as they do in any fishes activity.
    Just an observation.

  33. Triune says:

    Here’s another one most people missed: The last myth was based on a movie where the shark had been genetically altered to have human-level, or even above human, intelligence. It did very little throughout the movie that matched what a real shark of its species did, and often acted in ways that showed a high level of planning and intelligence.

    In other words, they tested a shark myth that is about a kind of shark which literally does not exist. The entire test fails simply because of that.

  34. Tim says:

    The magnet repellant test was not scientific, in that the size ratio of magnet to shark on the small species was not consistent with the bigger sharks. The thick highway of black magnets (nearly as wide as the shark) repelled the small shark. With the large species the relative equivalent of a few tiny magnets….c’mon. That was weak.

    • Borski says:

      I just watched an episode on sharkeweek where they showed the magnet worked against great whites…They had to add more to get it to move away from the bait so what gives?

  35. Paul Barnard says:

    We are about to go to the Keys for lobster season, We plan to put a light inside a 13 foot yellow Ocean Kayak (Prowler), the idea is to make it glow yellow. I know it will glow like a huge yellow light stick in backyard testing. This will make it easy for others boaters to see us making it safer for us to be in the water as well as make it easy for us to find the boat. My question is “Will this attract sharks to the Kayak during a night trip 3 to 5 hundred yards off the beach????

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