Articles, Blog

Shark Electrosensory Experiment | JONATHAN BIRD’S BLUE WORLD

September 12, 2019

This time on Jonathan Bird’s Blue World,
investigating shark electrosensory systems! Hi I’m Jonathan Bird, and welcome to my
world! I’ve been swimming with sharks for over
twenty years, and usually with a camera. One thing that has always been true about
sharks is that they seem to love my camera. Sharks get right up close to the lens. This makes great, dramatic footage. And lots of TV shows–not this one–try to
use this behavior to make sharks look aggressive. Well, it’s not aggression. They just want to be TV stars! No it’s not that either. Sharks have a snout full of pores called Ampullae
of Lorenzini, whose sole purpose is to detect tiny electrical currents in the water. All living things make tiny electrical currents,
and sharks can sense them. They use this skill to help them hunt in complete
darkness. My video camera produces a tiny electrical
field in the water, and it makes the sharks curious. They’re bumping the camera to investigate. During the day, this shark can see me with
its eyes…but in pitch darkness could it still detect my electrical signature? And from how away? To learn more about how the shark’s electrosensory
system works, I have come to one of the “sharkiest” places in the world—the Bahamas. And I just happen to have brought with me
an expert in shark electrosensory systems! Dr. Stephen Kajiura is a shark biologist at
Florida Atlantic University in Boca Raton. He is going to show me how sharks can sense
electricity with a simple experiment. Basically what we are trying to do here is
simulate the electric field produced by a natural prey item—a little fish or a crab
or something. All sharks have the ability to detect electrical
fields, and you can see those little pores all over the surface of the head—those are
all electroreceptors. So what we are doing is, by creating an electric
field in the environment here, what we will be able to demonstrate is the sharks orienting
to just the electric stimulus. We will have two identical targets, one will
be active, one will be a control treatment, and then you will see that they are going
to swim right over the control, ignore it completely, and bite only at the active electric
target. Dr. Kajiura puts the equipment together. We will take it underwater to do some tests
with the sharks. Dr. Kajiura, Julia and I gear up for a dive
to set up the experiment. Julia has brought down the plexiglass base. It will be partially buried in the sand so
it won’t draw attention to itself. Dr. Kajiura connects the electrodes to a cable,
so he can back up far enough to keep from affecting the sharks’ behavior. Next he buries the cables in the sand. Working underwater is slow going. Once everything is set up, he turns on the
power. Now a small electric field is emanating from
the experiment. Think of it like an invisible campfire on
the sandy bottom. It’s only warm if you are close. The sharks swim by, but they don’t detect
it any more than we do. They are way too high above it in the water
column to realize that anything is happening. After lunch, Connor, our shark handler, shows
up with some bait. He will use the bait to get the sharks closer
to our electrical campfire. The sharks are hungry, so they will focus
their attention on Connor, close to the sandy bottom. The Lemon sharks are swimming close to the
bottom now, looking for food. Dr. Kajiura turns on the power and we watch. The very first Lemon shark to pass over immediately
takes an interest in the plexiglass. It can clearly feel the tiny electrical field. A Tiger shark passes half a meter above the
experiment and doesn’t react. But another Lemon shark cruising just above
the sand homes right in on it. The apparatus is designed to produce an extremely
small electrical field, similar to the one generated by a living thing. We are talking about a super tiny current. Shark after shark stops to check it out–even
while Connor is feeding the sharks only a few meters away–but only the sharks that
are swimming close enough to the sand to feel it. This demonstrates how the electrosensory system
of sharks is only good for close range because the electrical field doesn’t carry far in
the water. They need to use their other senses like hearing,
eyesight, and scent to get close enough to prey for the electrosensory system to work. Sharks are amazing animals. They have highly-evolved senses to find prey. Ultra-sensitive eyes that can see in low light. A powerful sense of smell. They can detect the slightest vibrations in
the water that might be quarry. And when they get close to the prey–even
in pitch darkness–they have the ability to detect electrical fields. Some people think that because sharks have
been around for hundreds of millions of years that they are in some way primitive. But that’s completely wrong. Because they have been around for so long,
they have developed these incredible senses to give them the upper hand in the struggle
for life in the Blue World.


  • Reply Ryan Kang October 8, 2016 at 3:43 pm

    amazing video. I was always fascinated by sharks

  • Reply Yanghee Kim October 8, 2016 at 5:38 pm

    Hey Jonathan when are you going to see sleeper sharks, I'm not forcing you to investigate sleeper sharks I am just telling when you are going to record sleeper sharks. By the way I SUBSCRIBED ๐Ÿ˜€

  • Reply The Guardian October 9, 2016 at 5:22 am

    I noticed that almost every time the sharks bump into the camera they close their eyes.

  • Reply Antony thats good October 9, 2016 at 6:42 am

    thats good

  • Reply Matthew Jacob October 9, 2016 at 10:53 am

    U deserve more subs

  • Reply ุฑุงุจ ุงู„ูˆุทู† October 9, 2016 at 5:45 pm

    ุดูƒุฑุง ู„ูƒ ุฃุฎูŠ ุงู„ูƒุฑูŠู… ุฃู†ุง ู…ุฌุจ ุฌุฏุง ููŠ ู‚ุชุงู†ูƒ ุงู„ุฑุงุฆุนู‡

  • Reply Tim Howe October 10, 2016 at 1:14 am

    Thanks! As interesting as always! Can't wait for the next upload! ๐Ÿ™‚

  • Reply vhvhbb jbjhhh October 10, 2016 at 4:24 am

    im actually from Nassau,Bahamas and which part of the Bahamas did you go to film this video #242

  • Reply bianca sagona October 10, 2016 at 7:03 am

    i love all ur vids ! keep making pleae

  • Reply xUnique_lxnn0x October 10, 2016 at 7:24 am

    Shark episodes are the best

  • Reply Jim Schnurr October 10, 2016 at 6:03 pm

    Two questions-what is the double hose regulator for-(bubbles in back ?) and why the wet suit in Bahamas?

  • Reply soccer moments October 10, 2016 at 8:52 pm

    I have been subed since 12k sub's !!! but someone delteled you off my sub's I don't know why but your over 100k sub's!!! epic

  • Reply The Weeb Patrol October 11, 2016 at 12:58 pm

    Can you.see if the hammer head sharks ram with their head to get food I've heard the myth

  • Reply Star October 12, 2016 at 4:56 pm

    The Sharks bumping into the camera makes them look so cute <3

  • Reply tonadohunterjosh Storm TV TIV TEAM Jacarri October 13, 2016 at 7:48 pm

    This shirt has been distant the shirts not that dangerous just keep watching out for the sharks

  • Reply tonadohunterjosh Storm TV TIV TEAM Jacarri October 13, 2016 at 7:48 pm

    Give me Disneyland from great white shark

  • Reply tonadohunterjosh Storm TV TIV TEAM Jacarri October 13, 2016 at 7:49 pm

    You heard about the Megalodon Johnson bird

  • Reply First Name Last Name October 14, 2016 at 10:42 am

    I like how this show doesn't try to be dramatic like those Animal Planet shows.

  • Reply chunmei cen October 15, 2016 at 3:46 am

    do you know dantdm

  • Reply chunmei cen October 15, 2016 at 3:48 am

    fam lit

  • Reply chunmei cen October 15, 2016 at 3:48 am

    do you know pat and jen

  • Reply Wonder Twins October 15, 2016 at 4:20 am

    He never seems to upload enough videos for me to be happy ๐Ÿ™

  • Reply Duran boy Stubbs Jr. nick October 15, 2016 at 5:42 pm

    I am from the Bahamas

  • Reply Json07 October 15, 2016 at 9:36 pm

    Jonathan I heard some news about the great barrier reef died but them other people are saying it's fine. I believe it's fine maybe it's just a cash grab title. I wanna be a marine biologist and this kinda worries me. I know you know this the best, is the great barrier reef fine and ok?

  • Reply rumble fish October 15, 2016 at 10:24 pm

    could it be that the tiger shark was looking 4 a more intense electrical field which indicates bigger prey?

  • Reply Myggan October 17, 2016 at 12:31 am

    Have you ever seen a sunfish? And if not, can you try to make a video on that?

  • Reply Manchease Skrelpher October 19, 2016 at 10:49 pm

    1:47 Did that shark attempt to eat the remora that swam close to its mouth? Did you see that?

  • Reply Lisa Christine October 21, 2016 at 3:34 pm

    I love your videos!

  • Reply Gjon Goga October 21, 2016 at 5:24 pm

    well guess who is NOT taking his GoPro on a dive anymore :/

  • Reply Owning My Life October 23, 2016 at 5:21 am

    Really love your stuff really hope you get a mil subs

  • Reply Gaming Budds fans October 25, 2016 at 3:29 pm

    jonathan bird !! my son is passionate about animals and is passionate about you now that in his own youtube video he asked people to subscribe and like your page ๐Ÿ™‚ ๐Ÿ™‚
    please see below towards the end of the video

    I cannot thank you enough for how educative your videos are for him !!
    please see below :

  • Reply billy bob October 29, 2016 at 8:18 pm

    Some day l want to dive with you๐Ÿ˜€๐Ÿ˜€๐Ÿ˜€๐Ÿ˜€๐Ÿ˜€

  • Reply William Cox November 1, 2016 at 12:28 am

    Useful impressions of a complex sensory amalgam. Thanks for posting it, Jonathan and company!

  • Reply MicroActivist November 2, 2016 at 5:14 am

    Cool video..sharks are such incredible worth protecting!

  • Reply GamingWithDerpSans November 4, 2016 at 8:44 pm

    you said that the shark didnt react. well you were wrong look at the footage the sharks nose bumped into it.

  • Reply Itz me Jezzy November 5, 2016 at 1:07 am

    Like if you can see the dark in the right hand corner at 4:18

  • Reply Chona Lumba November 6, 2016 at 12:59 am

    wait your world, what did you made them be sure to your intro because it is gods world not yours

  • Reply Bill Luke November 10, 2016 at 3:51 am

    I wish I could go with you guys

  • Reply PROD APOLLO November 19, 2016 at 3:52 pm

    Is that a great white shark?!?

  • Reply maria picton November 24, 2016 at 10:13 pm

    What is your most love shark spisies?

  • Reply philistine adelaide sison December 3, 2016 at 3:52 am

    My curiousity is too much but like what are those fishes like white and black beside the sharks those fishes are always following them

  • Reply CII AS December 10, 2016 at 12:03 pm

    He deservers 1million subs

  • Reply Chi Dao January 7, 2017 at 2:01 am


  • Reply Chi Dao January 7, 2017 at 2:02 am

    Kem e

  • Reply Cindy Klenk January 8, 2017 at 8:12 pm

    Magnificent Johnathan! As an electrical engineer, and diver I have wondered what the (average) minimal electrical field is (mircrovolts?) – and does it vary by species. I keep hoping to see one of our elusive 6 gills on a dive up here in Puget Sound – so far – well they are elusive – have you seen them?. IMHO the charcarodon species is THE most perfect and magnificent species in the ocean (although I love our favorite Giant Pacific Octopods too ๐Ÿ™‚ )

  • Reply wickandde January 11, 2017 at 8:57 am

    Sharks are so cute

  • Reply Hayden Talbot January 11, 2017 at 6:53 pm

    Hi my names Hayden I'm 11 and I have been watching ur videos ever since I was little I would watch them literally 4-5 hours a day. U have inspired me to be a professional diver (I'm hoping to be taking classes at my lake house to become certified) I'm also rly want to make plans to go to all the Aquariums in the USA before I'm 18! I also want to be a Marine Biologist when I grow up and I have u to thank for all of that so……Thank You!

  • Reply midight brave January 23, 2017 at 5:53 am

    if you got more than 1 oxeygen tank, would you be able to stay underwater longer?

  • Reply Ruben Nouta January 25, 2017 at 7:06 pm

    Amazing. It is like they smell it.

  • Reply ฮœฮฑฯฮนฮฝฮฟฯ‚ ฮžฮตฮฝฮนฮฟฯ‚ February 7, 2017 at 11:30 am


  • Reply Twenty One Pilots was a Mistake February 11, 2017 at 4:18 pm


  • Reply M Younis February 15, 2017 at 4:20 pm

    sharks r my favourite animal

  • Reply Hugo Sanchez February 16, 2017 at 11:55 pm

    that is so cool

  • Reply crab guy February 17, 2017 at 9:05 am

    i also love animals so much๐Ÿ˜

  • Reply Otto Bauch April 2, 2017 at 3:41 am

    LOVE your videos , very relaxing to me and very informative, but why aren't you scared or uneasy about diving with wild sharks?

  • Reply fran bow April 12, 2017 at 9:16 pm

    I love the ocean so much๐Ÿ˜ƒ๐Ÿ˜ƒ๐Ÿ˜ƒ๐Ÿ˜ƒ๐Ÿ˜ƒ๐Ÿ˜ƒ

  • Reply Benjamin Mortensen April 13, 2017 at 10:04 am

    Cool cool cool

  • Reply Tziporah ladin-gross April 19, 2017 at 5:12 am

    low-key obsessed with you

  • Reply c XYZ April 21, 2017 at 8:48 pm

    Although the power of that device is obviously extremely low, still isn't it a bit too scary to play with cables in the water? XD That part was by far the scariest scene of Blue World series, in my opinion :))

  • Reply Charlie Cox April 24, 2017 at 4:39 pm

    You are awesome and I love you.

  • Reply RICKY VLOGS & TOYS May 2, 2017 at 1:44 am

    jonathan birds why sharks dont eat you

  • Reply cedric jay kenway May 4, 2017 at 5:15 pm

    can i ask if you have made a video about black tip reef sharks? ๐Ÿ˜€

  • Reply Gacha Girl May 7, 2017 at 11:23 pm

    Jonathan your name is my

  • Reply Gacha Girl May 7, 2017 at 11:23 pm

    Dads name

  • Reply Mikaela Chiombon May 15, 2017 at 12:50 am

    Jonathan this is soooooooooooooo inspiring

  • Reply sharky the 1st May 18, 2017 at 6:28 pm

    3:47 did anyone see the shark?

  • Reply fisherman Gannon May 27, 2017 at 3:12 am

    people think sharks are EVIL but they are not they just bite you to see how you taste but they don't like your taste so it is a axident! so don't kill sharks cause with out sharks oceans would be over polluted with fish, eels,urchins,crabs,any thing that lives in the ocean you can think of so never ever kill sharks !!!!!!!!!!!!!!!!!๐Ÿ˜Š PS: I๐Ÿ’™ sharks

  • Reply KB Daily June 27, 2017 at 9:16 am

    this is good Shark Electrosensory Experiment | JONATHAN BIRD'S BLUE WORLD.

  • Reply Annie Zaharov July 1, 2017 at 6:42 am

    can't even read the title sharks electro what?

  • Reply James _lol July 6, 2017 at 3:21 pm


  • Reply Stars for ever And ever July 7, 2017 at 5:05 pm

    Don't give up on your channel

  • Reply Stars for ever And ever July 7, 2017 at 5:06 pm


  • Reply Typical Asian Guy July 16, 2017 at 2:32 am

    You like wildlife, while I like tanks and battleships
    Animals are animals
    While battleships are animals to me and tanks and airplanes I have a powerful imagination…

  • Reply dleddy14 July 24, 2017 at 2:04 am

    Hi Jonathan. A question for you. Why don't the sharks detect your electric field and have you for lunch, especially those big tiger sharks?

  • Reply Kimber Lee August 7, 2017 at 12:59 pm

    So interesting

  • Reply Kannisa Saenkham August 11, 2017 at 9:30 am

    Does the sharks like it???

  • Reply sr. mono August 26, 2017 at 3:29 pm

    Jonathan would you go diving with mako sharks

  • Reply area51r September 9, 2017 at 12:10 am

    curious to your depth on this dive.

  • Reply Julia Le September 15, 2017 at 11:42 am

    That's must be hard making just a video

  • Reply Ergile September 30, 2017 at 1:00 am

    1:43 the shark gettin high af off those electrical fields look at his eyes lmao

  • Reply Jacob SkyKing October 7, 2017 at 5:03 pm

    Super interesting

  • Reply Caleb Chavez December 14, 2017 at 7:56 pm

    you are so cool

  • Reply Louismango/ Awesome Gamer 29 games February 6, 2018 at 6:58 pm

    4:17 who saw the shark in the background

  • Reply azzeddine Azzat zizo March 25, 2018 at 2:02 am

    Hey Jonathon how does the electrical wire inside water cannot shock you

  • Reply Zarah McIntosh April 15, 2018 at 10:57 am

    I wonder if there would be a way to install a device with electrical signals sharks would NOT like on surf and paddle boards.

  • Reply Oliver Rayner April 26, 2018 at 10:35 pm

    I agree sharks are not dangoiros i want swimming(aka fal in the water of my boat) with three kind of sharks in the water the kinds of sharks were defanitly bronze whalers and some people say that there are thashers and hammerhaeds there the hamer haed were on the other side of the island but were susposed to be were i was (i swas not on holiday its were Ilive)

  • Reply Prince Harry June 4, 2018 at 9:23 pm

    I love this

  • Reply Learn English With Ease June 7, 2018 at 6:06 am

    I can't believe my eyes!!!

  • Reply Anil Kumar June 20, 2018 at 5:08 am

    Great job Sir……….!
    Please tell me one thing…..
    Is it safe to dive in the oceans…?
    I mean, do sharks not kill the human beings? Other deadly animals like snakes do not affect the divers?

  • Reply Vapish June 23, 2018 at 3:07 pm

    Omg their eyes xd

  • Reply Sergio Ramรณn Rodrรญguez Cajiga June 26, 2018 at 10:44 pm

    With all those senses sharks are tremendous predators, but they behave like pets,… at least in your videos.

  • Reply Annoying dog July 5, 2018 at 12:41 am


  • Reply QF MR November 23, 2018 at 6:05 pm

    Wait shark is like a wire?

  • Reply Elaine B February 14, 2019 at 6:20 pm

    Upper WHAT??? Surely you meant upper FIN!!! Awesome though!!!

  • Reply Lisa Lein March 24, 2019 at 12:53 pm

    WOW I love it ๐Ÿ˜๐Ÿ˜๐Ÿ˜ โคโคโค

  • Reply Carl Blaskowitz March 31, 2019 at 1:00 pm

    Hey sharky.. you got meat chunks shooting out of your gills… slow down and savor your food properly.

  • Reply Matteo Pardi April 1, 2019 at 5:43 am

    1:47 the shark eats a fish just following him ๐Ÿ˜ซ๐Ÿ˜ซ

  • Reply Matthew Gardiner May 17, 2019 at 8:46 am

    I wish I could get certified but I have to save up 600 dollars Iโ€™m only 12 so thatโ€™s heaps to me but when I get it I will be diving 24/7 I canโ€™t wait it will take a long time but it will be worth it

  • Reply Vive le Fred August 15, 2019 at 10:25 am

    4:52 wow this Caribbean Reef Shark is the same size as this tiger

  • Reply Mike Malloy September 1, 2019 at 12:39 am

    As always I love your program and tune in at lunch time every day. However on your Shark Electro Sensory Experiment: I would like to comment. I see a design flaw with Dr. Kajiura's experiment with electro-magnetic energy. The main problem is that his neutral stimuli (control) and the experimental stimuli are with-in 12" of each other. If the shark approaches either one or the other then who is to say that the shark was not responding to the control stimuli vs. the experimental stimuli? In fact just random movement of the shark would put him in close proximity of one or the other. I would suggest separating the two stimuli by at least 15 to 20 feet, and not in the same plane. If they are in the same plane the shark could swim over one and also the other, thus from a statistical standpoint there would be no difference in the null. I would also manipulate the intensity and the frequency of the electro-magnetic field. This would produce a lot of data just ripe for publication. I think the design presented is worth pursuing but the methodology probably should be changed.. Mike Malloy, Corpus Christi, Tx.

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