Testing if Sharks Can Smell a Drop of Blood

I texted this clip to my wife who wanted proof I wasn’t doing anything stupid on a recent trip to the Bahamas Now if you’re wondering what my feet are doing in shark-infested waters with a bucket of blood 20 miles away from any land Well, that comes down to a conversation. I had with my friends at the Discovery Channel six months ago They told me Shark Week is coming up and they want to know what I would do if they could put me in the middle of the ocean on a boat surrounded by sharks for as long as I can remember I’ve always wanted to test if sharks can really smell a drop of blood in the water from a mile away Now before you say Mythbusters already did this They kind of did this as you can see to test this they poked their fingers and then stuck them in a barrel with these Tiny lemon sharks and since they didn’t really seem to turn around and look at their fingers They said it was busted now I’m friends with both Kari and Adam, but I think even they would have been at least in this case The methodology was less than scientifically rigorous so I came up with a more robust test procedure built some NASA great hardware for the experiment hopped on a plane and then a Speedboat and soon enough. I was 20 miles offshore of the Bahamas To kick things off I sat down with my marine biologist shark diving expert friend Luke Tipple and explained my plan in eventually Eventually I plan to test just how far they could smell a single drop of blood in the water But first I wanted proof that they actually preferred blood over any other scent So for my first experiment I plan to put four surfboards in the water equa-distant from the back of the boat each board would host two litres of a different liquid that we would pump into the ocean over the course of an hour then using A three meter radius around each board as a gauge we would use drone footage and count how many sharks went over to check out? Each board. So this board would be fish oil, which I heard was a general attractant for lots of fish Then we would have cows blood here Then sea water here as a control to make sure the Sharks weren’t just interested in the surfboard and then finally urine I’ve heard From surfers that a lot of them won’t pee in their wetsuits because they feel like it’s gonna attract a shark I don’t know a surfer alive who doesn’t pee in their wetsuit. But yes that’s definitely something that I’ve heard, a lot. It’ll liberate surfers everywhere, if we show it’s cool to pee in your wet suit. And so after a bit more discussion Luke was on board for the first of our two experiments Well as a firm believer in the scientific method, we’ll test it out And then you’ll dive Well, depending on the results I dive If I can’t pee, then the deal’s off And so with that we started putting the four boards together [Music] We also started collecting scientific donations from the crew All right, so now it’s time to fill these bags. Mm-hmm, what do you want to do first – pee or blood? Yeah, let’s do pee. Okay, let’s do rock-paper-scissors for who holds the bucket and who holds the bag Alright, one two three shoot? Ohh I gotta strategize… okay I know I know One two three shoot. Yeaaaa. Dammit Ohh that smells so bad It’s urine Whosever’s it is, they need to hydrate – dude this is going to be a nightmare. Oh it’s warm Your pouring sucks! Okay Oh that smell of All in the name of science That’s a great time of day to be doing this cuz we have a lot of sharks looking down here we got three or four lemons on the surface and I can actually see two Tigers down on the bottom and that’s actually a massive tiger shark That is huge All right, see if you can do it better job pouring than I did. Oh my gosh Oh wow. There’s a feeding frenzy It’s fine What do you mean don’t move it? I almost lost my hands They’re not gonna jump out of the water. Okay, so we’ve got sea water as our control, fish oil, we have urine, and cows blood So while Luke is bravely swimming the four surfboards out and anchoring them in place in preparation for the one hour countdown Now is a perfect time to explain the cool tech on each board I designed and built from scratch with my buddy Shawn Hodgins For this experiment to be robust All four boards need to start pumping at the exact same time after Luke has them in place That means we need to somehow start the pumps using a radio signal from the boat so each surfboard has a waterproof receiver box like this that also hosts the battery, a custom printed circuit board, and two Arduinos Then I have the remote control and as soon as I hit this button [mechanical whirring] They all start pumping at the same time We know each pump is working because the corresponding yellow light is lit up That’s important because they’re too far away from the boat to see if they’re functioning properly To pump the blood and pee We’re using a peristaltic pump this is a perfect choice because it’s a totally sterile way to get the blood from the bag to the Ocean since the blood never touches any sort of valve or something It just has these rollers that sort of pinch and push the blood through the tubing in a manner that just happens to be similar To a severed artery And so with the board’s in place It was go time operation shark bait test thing commence – three two one… beep All four going we have confirmation Everything is rolling. The experiment is underway. We’ll, let them go for an hour just dripping stuff out And yea we’ll see what happens. And after ten minutes I was really surprised there wasn’t a lot of action on any of the boards So so far. It’s pretty interesting I mean we’ve shown if you have a massive cut and you’re bleeding out and there’s this many sharks within like 50 yards of you that they’re kind of like ‘meh’ so like already that’s an interesting finding, right? You would think like a little bit of blood and there would just be a massive swarm But that’s not the case so far And to be clear we weren’t dealing with small quantities here the human body contains five liters of blood and after you use Two liters, which is the exact amount. We’re putting in the water then you die About 20 minutes in things were still pretty quiet, especially at the fish oil urine and control boards But then the blood board started attracting some smaller fish and soon after one or two sharks started taking notice Not a lot of love for my pee. I don’t know why I find that kind of offensive, but I’m just a little hurt Eventually with about 15 minutes left things started getting pretty wild over by the blood board The blood was spread out and made almost like a blood run way So you have the surreal line of sharks swimming up this Enticing blood trail one after another only to be super disappointed to find a big piece of styrofoam We’re almost done Three-two-one, the motors have stopped our experiment is done. I just like to point out the bags have been sucked dry So the engineering part of this experiment was flawless Gunshot everywhere. Yeah, no to super pissed off targets and so now it’s time to go in and review the footage and get a final tally for each board and what we found was that four sharks went to check out the fish oil then zero sharks went to check out both the control and The urine and then the blood board had a direct visit from a whopping 41 sharks and so now that we debunked some surfing myths about Urine and proved that sharks certainly had a strong preference for blood over anything we tested the real question was Just how much blood is interesting to them and there was one part of the experimental design That was really nagging at me. Cuz that was cows blood right that was cows blood. You wanna try human At least 10 living braiding blood bags around here Not everyone was luke and I about this idea Yeah, and then just draw will just have fresh blood just mainline it and put it in the water one up. Would you be down? Moondog, what do you reckon look at me? So Luke made some calls and soon enough we had an amazing certified bhajami and phlebotomist on board And after some generosity from the camera crew and even captain Scotty We had four bulging bags of human blood for our second experiment This is my actual blood free to see if sharks have a taste for it And if they do I probably won’t go three dining with them for the second experiment. We had three boards again We placed the control in the middle the board over here would pump the human blood Slowly at one drop a minute and then on the other side this board would pump the blood fast on average one drop every four seconds we were able to do that because another cool feature for the boxes we built was that by turning This knob you can control the flow rate So over time they can pump out different amounts and because sometimes we all have to step up and just do our part while Luke Once again risked his life by placing the three boards. I’d prepared to push a button All right, all of them are popular and good to go now the clock is ticking So we have like fifty five more minutes to go We’ll see if the Sharks notice there One drop of human blood every four seconds may sound like a lot and it certainly is but it’s also important to note That’s 40 times less than the first experiment where we saw so much activity in this case halfway in to experiment number two Even though there were tons of sharks still in the area. The boards themselves were pretty quiet We’ll have to see when we look at the footage afterwards. But so far it looks like the answer’s no Five four three two one Experiments over and so after the full hour we brought in the board’s and once again reviewed the footage to see that over the course of an hour zero sharks two checked out the control board zero checked out the slow blood pumping board and Exactly zero sharks checked out the fast one So this is by no means a perfect experiment but I think it’s safe to Qualitatively say that if no sharks came to check out 15 drops of human blood a minute in the middle of shark-infested Waters and probably gonna be okay with a small scrape I mean there certainly won’t be some kind of feeding frenzy with a single drop of blood from all sharks within a mile Now that I had some first-hand data to put my mind at ease I was willing to try diving with the sharks without a cage, but I had one final experiment I had a theory that if we secured a 360 camera to the front of a hand spear and then shot it near some sharks We could create the world’s first really cool matrix, like underwater bullet time effect. So I suited up and goddamn I Like theory proved correct on the whole time ham spirit because as you can see that footage What I’ll take home from this shoot is just more evidence of the amazing animal that sharks are but also the ability to point people in a specific direction to say Hey your thoughts about them are a little overblown this experience. Definitely changed my perception on sharks I would say I respect them more after seeing their raw power up close at the same time There’s less of that fear that comes from ignorance on top of all that I didn’t die 14 years ago when I was just a wee lad working for NASA. I remember getting my first ever bonus check for some work I did on the rover my whole life. I’d always wanted a really nice pair of headphones So I splurged and got these bad boys. So the Bose QuietComfort 15 s and as you can see I have used them extensively For the past 14 years Especially when traveling in preparation for this trip to the Bahamas both sent me some of their brand new headphones 700s So I used them for the whole trip and for the past couple weeks now, you should know both supported this video But they didn’t give me any specific talking points to say besides tell people what you honestly think and so after using them for two weeks what I honestly think is that if this represents my old headphones This represents my new ones these things are a total GameChanger And so here’s what I think are the four coolest features first off The noise cancelling is insane without actually trying these on it’s really hard to demonstrate on video. But here’s my best attempt this week The candlelight but you were to comb it I answered all these headphones this is exactly what my voice would sound like number two They are totally wireless with a battery charge of twenty hours. This was plenty for me. Never even to get close to stranded But if you do run it all the way down, they utilize quick charging So 15 minutes of charge time from a totally dead battery gives you three to half hours of listening and if your battery is somehow Totally dead with no way to charge you just open this clever Compartment and then you just plug them in and then you can still use them as passive wired headphones number three They have hands-free mode. So you never need to pull your phone out of your pocket Hey Alexa, play songs by hand rapidly You can also use the touch sensitive side to pause and skip songs and change the volume And finally, one of the coolest features is conversation mode this gives you super hearing and uses all four mics to actually pass in all the sounds from around you so you can actually have a conversation with someone without having to take them off and so while I’m no mkbhd That’s my tech review. I love these things and they’re super comfortable It’s like wearing a pair of clouds over your ears that can totally block out the outside world But also happen to have amazing sound quality. So thanks to Bose for making an amazing product and thanks to you for watching

100 thoughts on “Testing if Sharks Can Smell a Drop of Blood

  1. What if u used u know that white sticky fluid with comes from a weird looking tube…. U know what i mean….


  2. So yeah, I’m starting another myth. Sharks cans feel your movement in the water from ten miles away

  3. Could have something to do with the sharks might be used to getting food from boats that go to that area and feed them

  4. Bruh i wanna go there so bad…the water looks so clear and it’s cute how the baby sharks swims with their parent ?

  5. There’s nothing more terrifying than seeing a huge tiger shark right below you when you where just snorkeling with turtles 🙁

  6. wuuut thats so much blood you just took outta ur body and donated it to the sea (im sorry thats the only way i can describe that?)

  7. I thought this was gonna be some type of annoying Jake Paul type vlog-stunt, but it turned out to be done nicely and interested me.

  8. I think that you might try seeing if they’re more responsive to movement then no movement. Maybe like adding a motor to a surfboard and no motor and a control much like the second experiment but have them at the same release speed like the first test. But overall super cool and an interesting video

  9. The way the sharks were congregating at the stern of the boat it seemed that they may have been preconditioned to go there. Maybe because of fishing excursions or shark tours that would throw fish guts or feed them off of the stern.

  10. Sharks : lets eat this guy
    Sharks : shut up they have a camera
    guy : hey sharks
    Sharks : hahahey we love humans but drop your camera to get big welcome 🙂

  11. Have you considered the possibility that they might have habituated to the blood and started associating it with a non-prey object (the board)?

  12. They don’t realize that they were the variable, the sharks were gathered around the boat because the sharks know that the boat throws chum into the water.

  13. Maybe they didn't go for the human blood because the smell of the cow blood was already in the water?? It could have also been because they went for eh cow blood and there was nothing there so they might not have bothered? Idk how smart sharks are so my last statement could be wrong but just a thought i guess.

  14. I wonder if the boat had a factor in the isolation of the scent tho. The vibrations and physical size of the boat I think had a big part in the ignorance of the different fluids. Would love to see this same experiment done, but with the boat 2/300m away


  16. Is it just me or is the data a little skewed, since the boat itself seemed to attract much of the sharks’ attention? Wouldn’t the data be far more accurate if they did this experiment but watched from the air without a boat so there was no distraction? Yes I’m aware that would be very tough.

  17. as far as the literature about sharks i've read told me, sharks seem to be very picky in choosing their food and human seems to be too low fat for sharks. They go much more for fish. and since a shark is a fish too, wounded, bleeding sharks seem to have real problems with their mates. That shown in a documentary (and i'm not talking about the "documentary" by pixar) they are totaly capable of cannibalism (maybe pixar isn't that wrong after all on this one), but very unlikely too taste human meat. This would explain why annually only around 5 people die by shark bites worldwide. many more humans survive when beeing accidentaly bitten by a shark. Considered that sharks are some of the best swimmers on the planet many times faster and quicker than a human moving through water, it's totaly up to the shark whether he would or would not eat a human now and then and human and shark meet quite often. if sharks could not distinguish that well, this video would have cost more than 4 small voluntary bags of human blood.

  18. the human blood didn't work maybe because you guys tricked them with the cow's blood which they thought was food lol i'm not so sure but that's what i thought

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