Hammerhead Shark Mystery | JONATHAN BIRD’S BLUE WORLD


Today, Jonathan investigates sharks that tilt
when they swim! Welcome to Jonathan Bird’s Blue World! The underwater world is full of mysteries
to be solved. One such mystery involves the Great Hammerhead
shark. Divers rarely see Great Hammerheads…they
are known for being shy loners, unwilling to approach people. But a few years ago, divers began visiting
a place near Bimini Island in the Bahamas, where Great Hammerheads have been caught by
fishermen for years. They found a special place with lots of sharks. Over time, the sharks got used to divers and
started coming in close for a snack, giving people an intimate look at the Great Hammerhead
shark. I have been to Bimini several times and I
am always amazed by how huge Great Hammerheads are. Not only does the head reach a meter or more
wide, but the tall dorsal fin is a striking feature of this unique and majestic shark. And in spite of the aggressive appearance,
Great Hammerheads almost never attack people. They much prefer to eat stingrays in the sand. But diving with Great Hammerheads has allowed
divers to notice something unusual—the shark often swims tilted to the side at an angle. I also noticed this behavior in the Ocean
Voyager Exhibit at the Georgia Aquarium. My friend Andy Casagrande—one of Discover
Channel’s primary Shark Week cinematographers—wanted to help investigate the mystery of the leaning
Hammerhead. He attached a GoPro camera to the huge dorsal
fin of a Great Hammerhead, to film the shark for an extended period of time. His amazing footage shed light on the behavior
of these sharks…and it has to do with their anatomy. The hammerhead shark never stops swimming. But, contrary to popular belief, many sharks
do. Most species of sharks, like the lemon shark,
can rest on the bottom and move water over their gills by simply gulping. Biologists call it “Buccal Pumping.” A few species of sharks, like the Whale shark
and the White shark, are known as Obligate Ram Ventilators. They can only breathe by ramming oxygenated
water into their gills through their mouths as they swim. If they stop swimming, they’ll suffocate! The Great Hammerhead is also an Obligate Ram
Ventilator, and has to keep swimming. Sharks such as the Blue shark keep swimming
all the time too, but for a totally different reason–because sharks sink if they stop swimming. Fish, including sharks, are heavier than water,
so they sink. Bony fish have an organ called a swim bladder
that they use to adjust their buoyancy. By adjusting how much gas is in its swim bladder,
a fish can keep itself perfectly neutral so it doesn’t sink or float. Since sharks have no swim bladder, they sink
to the bottom when they stop swimming. But some sharks like the Blue shark live in
the open ocean where the bottom is thousands of feet below where it’s dark and cold. They can’t rest on the bottom. So they have adapted to this environment by
developing very large pectoral fins to act as airplane wings. As the shark cruises through the water, the
fins provide lift to keep the shark aloft, and prevent it from sinking into the dark,
cold abyss. The bigger the pectoral fins, the more lift
they provide, and the slower the shark can swim without sinking, which saves energy. The Great Hammerhead on the other hand has
small pectoral fins and a big head called a cephalofoil. The cephalofoil seems to accomplish several
things for the shark, including expanded vision, a larger surface area for electro-receptors,
and additional front end lift like a mini-wing. But it also has mass, and scientists think
this mass, combined with small pectoral fins, is the reason that hammerheads are so much
more maneuverable than other similarly-sized sharks. But while those small pectoral fins help the
shark turn quickly to catch prey, they have a disadvantage: not much lift. And this is where the tilted swimming comes
in. Andy Casagrande’s dorsal fin footage showed
that when Great Hammerheads are on the move, they are almost always swimming at a tilted
angle of more than 45 degrees! In 2015, Nicholas Payne, Gil Iosilevskii and
5 other researchers got together to investigate this strange behavior. They put sensors on Great Hammerhead sharks
to measure the roll angles. Then they used wind tunnel tests to model
the effect and figured out what the sharks are doing. The sharks roll on their sides to use that
huge dorsal fin as a wing and provide lift while swimming distances. It allows the shark to generate more lift,
which means it can swim a bit slower without sinking, and save energy. In fact, swimming tilted to the side saves
the shark about 8% swimming effort. So when the shark needs to go somewhere, it
tilts to the side and saves energy. But when it needs to hunt, it swims straight
up and down to take advantage of the increased maneuverability. The giant dorsal fin serves two purposes…a
keel when upright, and a wing when tilted! At this point, no other shark is known to
use this technique, and it explains a mysterious habit that divers observed in Great Hammerhead
sharks. Sometimes just being in the ocean creates
new understanding of the life that lives there. As divers, our time in the ocean is fleeting,
lasting just an hour or so per dive. But it affords us the opportunity to catch
a glimpse of the lives of the animals that live there. This is one of the things that keeps me coming
back over and over, for my short glimpses into the Blue World.

100 thoughts on “Hammerhead Shark Mystery | JONATHAN BIRD’S BLUE WORLD

  1. Hello, Jonathan. I just recently am getting my SCUBA certification. I was wondering if you knew any must see dive sights in Florida?

  2. Can you a second Basking Shark video? Like, not pictures. Just an actual shark. People are confused because think that Basking Sharks are larger than Whale Sharks.

  3. Very cool! The "small wing," as you put it, would be called a canard on an aircraft. The Concorde SST had them, as do several of Burt Rutan's aircraft designs.

    And since you mentioned it, http://www.georgiaaquarium.org/

  4. Your videos are like watching my dreams right in front of me. I love your videos. You're my inspiration Jonathan!

  5. Dont think the cephalofoil is used for hydrodynamic purposes. It would automatically tilt when they would use it for fast turns. And that they tilt their whole body while travelling speaks against the "mini wing-theory".

  6. Hey Jonathan, keep making videos they help me with anxiety pretty well so far as weird as that sounds. Whenever I'm having trouble with insomnia I just play one of your video playlists and end up falling asleep. ( not meaning to say that they are boring, it is relaxing to watch ) I also watch them in the morning 🙂 By the way I like sharks and I want to be a scuba diver.

  7. Amazing video and great explanation! I went shark diving this year. First in Florida where I saw Lemon, Bull, and Sandbar sharks. While I was there I met Jim Abernethy, and I July I went to Isla to swim with Whale Sharks. That was an amazing experience. I have a few vids from FL and Mexico. I loved sharks since I was a kid, and when I spent time with them in the water my love just skyrocketed towards them. I do some conservation work now. While I was in Mexico I also met Shawn Heinrichs. Mexico was lots of fun. Some ppl even saw dolphins. I saw a huge manta though. Probably Oceanic Whitetips are next. I 💙 those sharks! Great vid + 👍

  8. My window to my passion wile im working in the center of the countryside (Madrid) im from canary islands. Thanks buddy e ir your work, you and your team are world class.

  9. Imagine the 1st hammerhead to discover this technique like:
    "GUYS!!! GUYS!!! GGUUUUUYYYYSSSS!!!!"
    "we don't care Nathan…"
    "Fine…WEEEEEEEEEEE!!"

  10. My son's and I have recently found your channel and we love it! My 7 year old son has always wanted to be a diver when he's older and the 9 year old is thinking a marine biologist, so these videos are great educational and interesting at the same time! Thank you 🙂

  11. Jonothan, Ya Did It Again!!
    Nice Video.. I've Been Watching Since 100 Subs!!! I Remember You From When I Was 6.. (I'm 9 now)

  12. I hate the feeling of being INSANELY curious and interested and ABSOLUTELY terrified at the same time (for example great white sharks) I mean I am insanely afraid of meeting a huge shark in the open ocean but I'm also iterested in sharks

  13. So, Do sharks ever sleep Jonathan? If so how? Where do sharks get their energy from? Btw I love your channel!! Recently subscribed and can't stop watching. Thank you !😊

  14. If you dont mind me asking i have a few questions about sharks

    -Can sharks smell human blood
    -What is the most dangerous shark and in what country are they mostly found in
    -Will sharks eat dolphins and penguins
    -What is the least dangerous shark in the world
    -What are the best ways to aviod getting attacked by a shark

  15. Wow, plenty of information packed into under nine minutes!
    My toddler loves your videos and I'm really enjoying learning so much. Thank you, Jonathan! x

  16. I have a small issue with your shark videos. They are addictive! You have created a format that includes so much information in a short amount space. I actually find myself wanting to dive with these amazing creatures.
    Thanks to you Jonathan and your crew for such wonderful videos.

  17. Very interesting. I didn't know this species of shark often swim tilted. Now, I understand more the relationship between shape and function in these magnificent animals.

  18. Yes, but has anyone figured out why the hammerhead evolved the shape of his head? I think this is a much bigger mystery!

  19. Hey Jonathan how about going to oroquieta city in the Philippines thats were I live and I bet you might see some amazing creatures of the blue sea if you go their please invite me at upper loboc purok 5 close to Zaldi Daminar and ask some people were can you find the abuhon house because Im not really rich and not poor just neutral please.

  20. HOW HUMANS COULD KILL THOSE BEAUTIES OF THE OCEANS,MAKES ME MAD AND HATE COMES UPON ME…..THE TAPES OF THE MOVIE"JAWS" SHOULD BE DESTROYED FOR EVER……AND SHARK"FINNING" boats Sunk….Shark floating lines destroyed….OCEANS AND SEAS ARE NOT OURS……HUMANS HAVE DONE SO MUCH DAMAGE ALREADY………

  21. Wait why don’t u attach a camera to the dorsal fin and live stream it for all of the hammerheads life????????? I’d really wanna see that

  22. at first I hated how scary sharks were…then I wached only 3 of you're vids and now my mom will be planing for us to dive with tiger sharks

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