A YouTuber tested if sharks can actually smell a drop of human blood from a mile away

7 August 2019, 17:36 | Updated: 7 August 2019, 17:37

Can sharks smell blood?
Can sharks smell blood? Picture: YouTube: Mark Rober

By Staff

YouTuber Mark Rober tested out the popular theory in a new video.

Sharks get a pretty bad rep in popular culture, with almost every film from JAWS to Finding Nemo portraying them as blood-hungry villains. But are they really so bad? Can sharks really smell blood underwater? Am I going to be safe if I decide to go for a swim at the beach?

That’s what popular science YouTuber Mark Rober tried to find out in his latest video, called ‘Testing if Sharks Can Smell a Drop of Blood’, using a series of science experiments. The results weren’t exactly what you would expect either…

Mark and his team tested how a group of sharks reacted to four different liquids - blood, fish oil, urine and a control of sea water - as they were slowly emptied into the water by a machine from a surf board. They opted to do the test twice, for an hour each, once using cow’s blood and then again using human blood volunteered from the team and video crew.

The first test with cow’s blood showed the sharks pretty hesitant to approach any surf board for a while, but by the end of the test forty sharks had come over to investigate the ‘blood surfboard’, with the other liquids getting no interest or only a very minor one.

They then repeated the test with human blood, but interestingly found that the sharks showed interest in none of the boards.

Mark concluded: "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, you're probably going to be okay with a small scrape.”

"There certainly won't be some kind of feeding frenzy with a single drop of blood from all sharks within a mile."

We can safely say we’re glad to hear it.