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Testing if Sharks Can Smell a Drop of Blood



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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