THIS GRISLY experiment has revealed whether sharks prefer human or fish blood.
YouTuber Mark Rober teamed up with the Discovery Channel to conduct the shocking experiment in The Bahamas.
The former NASA engineer shared his documented experiment to YouTube and the video - titled 'Shark Attack Test- Human Blood vs. Fish Blood' - has since obtained more than 14million views.
However, cow blood was used instead of human blood because “all mammal blood essentially smells the same to sharks," Rober explained.
In the now-viral 18-minute video, Rober said it's also "really hard to legally find five gallons of human blood."
The experiment was conducted with three surfboards - each containing something different.
One board had a five gallon bucket of mammal blood, another had a five gallon bucket of fish blood, and the third had seawater.
The seawater was used as a control, "to make sure the sharks weren't just interested in the surf boards," Rober said.
A pumping system was used to push the blood steadily into the ocean water.
The process of pushing the three different substances out into the water took one hour.
"We basically placed the boards in the middle of the freaking ocean, super far away from the boats, so it wouldn't be a confiding variable," Rober explained, noting that they learned from a previous experiment.
He added: "One of the limitations to last years test, was that the boards might have been to close to the boat, so its possible some of the sharks actually smelled the blood, but didn't investigate it because they were just waiting for a handout from the boat.
Rober and his teammates watched drone footage from the boat to see how the sharks reacted to the surf boards.
Even though the first shark was spotted at the mammal board 20 minutes into the experiment, the board with the fish blood was approached the most.
According to the test, sharks were found to prefer fish blood.
The mammal blood was approached eight times, the seawater was approached zero times, and the fish surf board had a high total of 134 approaches.
Rober said in the video: "The main takeaway for me from this experience is that sharks have been on this planet longer than the dinosaurs, or even trees have.
"So they've had 400 million years of evolution to develop these instincts that are rewarded for smelling fish blood.
"Humans and cows will be an extremely rare delicacy so it makes sense that it's just not hardwired into their brains."
He also said that their findings "busted the myths of the movies that sharks are these ruthless killers that just go crazy if they smell a drop of your blood."
train TRAGEDY3 dead including driver & 6 others injured as train derails in 'landslide'
TEEN RAPEBoy, 13, arrested after teen girl raped in park in broad daylight
HOT SPOTSInteractive map reveals if coronavirus cases are rising in YOUR area
crikey!Bindi Irwin, 22, pregnant with first child 14 years after the death of dad Steve
HOLIDAY HORRORHoliday park landslide sends caravans crashing down hill as 500 evacuated
SHALLOW GRAVE MURDERTeen 'prowler', 17, killed mum and tried to chop up her naked body
The following day, Rober and his teammates made the most of their trip to The Bahamas - which they flew on a private jet to - and released a "fish-blood smoothie" to sharks from an underwater cage.
When Rober - who was placed inside the human-shaped cage - opened up the blood bag, the footage made for a frightening scene and at one point a shark made its way inside the cage.
He called it a "shark-feeding frenzy."