Sharks are some of the most well-adapted predators that live in our oceans, which is where they get their fierce reputation from.
They have incredible hearing, so much so that they can hear a dying fish’s heartbeat. But what about their smell. Can sharks smell blood?
In short, yes sharks can smell blood. A shark’s sense of smell is so strong that it can smell a single drop of blood from as far as a quarter-mile away.
Let’s take a closer look…
Will A Shark Attack If It Smells Blood?
Sharks are not the blood-thirsty monsters that the media portrays them as. They do not go into a hyper-predatory mode when they smell even a drop of blood, this is a myth.
Whilst they are able to smell blood from an impressive distance, they do not enter a frenzy and start attacking everything in sight.
This myth has given people fear to even step into the water with a tiny cut on their finger, when this really shouldn’t be the case.
There have been many experiments done to test out this myth, which ultimately proved to be wrong.
Like the one done by former NASA engineer Mark Rober and marine biologist Luke Tipple in 2019 as part of shark week.
They used devices to pump out cows’ blood, urine, seawater, and fish oil over a one-hour period to see which one would grab the attention of sharks in already infested waters.
Four sharks went to the fish oil, none to the seawater or urine either. However, after 45-minutes around 40 lemon sharks investigated the cow’s blood, as you would expect.
But this experiment goes to show that even in shark-infested waters, sharks do not go into a frenzy over a single drop of blood.
They also went further and tested donated human blood, one that pumped out slowly and one that pumped out quickly. No sharks we’re interested in human blood.
Is A Sharks Sense Of Smell Good?
A shark’s sense of smell is incredible and absolutely necessary for survival in the wild. These predators have some of the best senses of all animals, allowing them to detect prey easily.
Let’s take a look at how a shark’s sense of smell works. Just under the shark’s snout, there are two small openings or nares, which are nasal cavities.
Each cavity consists of two more openings, water travels in one opening and then leaves through the other.
Inside the cavities are a series of sensitive skin folds. Water passes over sensory cells within the skin folds.
These cells pick up scents in the water, which then send signals to the shark’s brain. Once in the shark’s brain, the olfactory lobes kick in and analyze the scents, often associated with either prey or a mate.
From here it’s up to the shark to interpret the smell, and decide whether it wants to act on it or simply ignore it.
Sharks have a sense of smell and olfactory system that is hundreds of times stronger than that of a human, their nostrils are used specifically for smelling, and not breathing.
But it’s also the ocean that helps sharks have such a great sense of smell. The motion of the ocean literally carries smell molecules with it, further enhancing their sense of smell.
How Far Away Can Sharks Smell Blood?
Thy myth that sharks can smell a drop of blood from multiple miles away is, well… a myth.
Yes, sharks do have a great sense of smell, but they are unable to smell a drop of blood from multiple miles away as the myth suggests, this has been heavily exaggerated.
The truth is, some species of sharks are able to smell a drop of blood from as far as a quarter-mile away, but it does depend on some variables.
This is optimal and requires everything to go in favor of sharks to be able to smell blood at this distance.
The water current plays a role in the distance sharks can pick scents up from, largely because scent particles get diffused by the water.
It takes a long time for scents to travel once they are diffused in water, therefore the faster the current, the more quickly sharks can pick up a scent.
Can Sharks Smell Fear?
Another common myth around these marine predators is that they can actually smell fear. This is false.
Sharks do have an exceptional sense of smell, but they certainly cannot smell a person’s emotions, which includes fear.
That said, sharks do have electro-sensing abilities, which means they can detect the electronic currents that go on in prey, such as their heartbeat.
They can sense and detect their prey’s heartbeat from a distance of around 100 meters, which makes them so efficient at hunting in low light.
This is because whilst other animals are relying on their sight, which is dimmed at dusk, sharks rely on their many other senses, giving them an advantage.
This electro-sensing ability allows sharks to detect if their prey is panicked by them, and gives the shark a better indication as to whether they should attack them or not.
Can sharks smell blood? Absolutely, but the distance they smell it from is massively overblown.
If conditions are optimal and there is a strong current, some sharks are able to smell a single drop of blood from up to a quarter-mile away.
However, this is not the case for many species, and if there is no current. You should not be panicked by myths that are set out to make sharks seem like bloodthirsty monsters.
It’s true that sharks have an array of amazing senses, which makes them the formidable predators that they are today.
Hopefully, this post has been helpful and you’ve learned a thing or two about how far sharks can smell blood.
Thanks for taking the time to read this post and feel free to share it with others who may find it of value.
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Hi, I’m George – the founder of MarinePatch. I created this blog as marine wildlife has been my passion for many years and I’ve spent decades learning and dedicating myself to documenting all I can about the topic.