Do sharks like human blood? Sharks have long been the subjects of fascination and fear. With their sleek bodies and rows of sharp teeth, they are often portrayed as voracious predators.
This topic has been the subject of much speculation and sensationalism, fueled by movies and media portrayals.
However, it is important to separate fact from fiction when discussing the preferences of these apex predators, and that is what this article is all about.
Well, look at some scientific evidence and shed light on whether or not sharks have a particular affinity for human blood.
Do Sharks Like Human Blood
Sharks do not like human blood, as you would imagine. But don’t get the statement wrong. Sure, they may detect blood through sight, smell, or taste and swim to the source to investigate out of curiosity as most predator fish would. But that doesn’t mean they like it.
There is no scientific evidence to support claims that sharks like human blood. In fact, one experiment by Rober supports the idea that sharks do not prefer human blood.
An Experiment Conducted To Test Whether Sharks Prefer Human Blood
Mark Rober, a former NASA engineer now a science YouTuber, conducted tests to determine if sharks prefer human blood.
It involved attaching pumping devices containing cow blood, fish blood, or seawater to three surfboards, which were then released into the ocean. As the surfboards moved, the pumping devices dispensed the fluids into the water.
Using a drone, Rober closely monitored and recorded the frequency of shark visits to each surfboard over one hour.
As expected, no shark was observed approaching the surfboard with seawater. Eight sharks visited the surfboard with cow blood, and the surfboard with fish blood experienced 134 shark visits.
So, what do these observations mean? The data strongly indicated that sharks are more drawn to fish blood than humans.
(And this makes sense. Think of it this way: since they feed on fish, they are used to their blood, and sensing fish blood triggers their mind and tells them it’s meal time. Which is why you probably saw 143 sharks visit the surfboard with fish blood.)
How Often Do Sharks Attack Humans?
Truth be told, the media is somewhat overdoing it in portraying shark attacks by giving the impression that they occur frequently. In reality, the occurrence of shark attacks on humans is rare.
According to a global survey, shark attacks result in approximately 10 fatalities annually, and only about 7% of unprovoked shark bites lead to death between 2000 and 2009. This statistic roughly equates to an average of 4.6 fatal bites per year.
Out of five hundred species of sharks, it was discovered that three specific types of sharks caused the most attacks: the great white shark, the bull shark, and the tiger shark.
These three species were found to be responsible for over 60% of all reported shark bites and a staggering 80% of the shark bites that resulted in casualties.
What Other Things Attract Sharks?
While many people know that sharks are attracted to the scent of blood in the water, several other factors can also draw these predators. These include:
1. Sound – Sharks have an incredible sense of hearing, capable of detecting low-frequency sounds and vibrations over vast distances.
Sounds generated by struggling fish or injured marine animals can alert sharks to potential prey.
However, you should note that not all sounds attract sharks. For example, the noise created by loud ship horns, motors, or engines is generally not appealing to them.
2. Color – Sharks are often portrayed as attracted to red, but this is a misconception.
Sharks are more attracted to high-contrast colors, such as black and white, rather than specific hues. It is because high-contrast colors create a visual stimulus that sharks associate with potential prey.
3. Food – Food is perhaps the most obvious attraction for sharks. As apex predators, sharks rely on a diet of fish, seals, and other marine animals.
The scent of blood and the presence of injured or dying prey can trigger a feeding response in sharks and draw them to a specific location.
This is why shark attacks are more likely to occur in areas where food sources are abundant or where fishing activity is prevalent.
4. Jewelry – Jewelry may seem unusual to attract sharks, but there have been cases where shiny objects, such as metal jewelry or diving equipment, have caught their attention.
Sharks are naturally curious and may investigate unfamiliar objects in their environment.
5. Electromagnetism – Sharks have highly sensitive electroreceptors called ampullae of Lorenzini, which allow them to detect weak electrical fields produced by living organisms.
Some studies suggest that electromagnetic fields generated by electronic devices or power lines could potentially attract sharks, although further research is needed to understand this phenomenon fully.
Which Sharks Are Most Dangerous?
Regarding the reputation of sharks, several species often stand out as the most dangerous due to their size, predatory behaviors, and documented record of attacks.
- Great white shark – The great white shark, known as Carcharodon carcharias, is perhaps the most iconic and feared shark species.
Renowned for its immense size and powerful jaws, it has been involved in many shark attacks on humans. However, it should be noted that great white sharks do not actively seek out humans as prey.
- Bull shark – Bull sharks, scientifically called Carcharhinus leucas, are notorious for their aggressive behavior and ability to thrive in saltwater and freshwater environments.
Their proximity to coastal areas and a willingness to enter rivers have led to more frequent interactions with humans, making them a potentially dangerous shark species.
- Tiger sharks – Galeocerdo cuvier- are known for eating various prey items, including non-food items found in their stomachs.
While tiger sharks are responsible for some shark attacks on humans, their danger is often exaggerated, considering the vastness of the oceans.
- Grey nurse sharks are large, slow-moving creatures with a somewhat menacing appearance due to their ragged teeth. They have suffered significantly from human activity and are now a protected species in many regions.
- Blue sharks – Prionace glauca are known for their striking blue coloration and are a common sight in open ocean waters. Commercial fisheries more often catch them.
- Mako shark – The mako shark, Isurus oxyrinchus, is a fast and agile predator. While they can be aggressive when hooked by fishermen, mako shark attacks on humans are exceedingly rare.
How Many Senses Do Sharks Have?
Sharks, apex predators of the ocean, have a range of senses that enable them to navigate their environment and locate prey efficiently. These include:
- Hearing – Sharks have an acute sense of hearing and can detect low-frequency sounds from a significant distance.
This ability is crucial for sharks to locate potential prey and communicate with other sharks nearby.
- Smell – Their olfactory system is highly developed, enabling them to detect even the faintest traces of odors in the water.
They can easily detect the scent of blood from miles away, enabling them to find injured or dying prey.
- Lateral line – The lateral line runs along the length of a shark’s body and consists of a series of sensory cells that detect changes in water pressure and movement.
This allows sharks to perceive their environment more accurately, especially in low-light or murky waters.
- Pit organs are located on their heads and are sensitive to electrical fields. These organs allow sharks to detect the electrical signals produced by living organisms.
This sense is particularly useful when hunting for hidden or camouflaged prey that other senses, such as sight or smell, may not easily detect.
- Vision – Sharks have eyes and can see, but their visual acuity is not as well-developed as their other senses.
Sharks primarily rely on their other senses to hunt and navigate their environment, with vision supporting them.
- Lorenzini – Some sharks have specialized structures called Lorenzini ampullae, which are small pores on their snouts.
These pores contain sensory cells that can detect changes in water pressure caused by movements of nearby objects. This lets sharks perceive their surroundings more detailedly, even in dark or murky waters.
- Touch – Sharks also have a well-developed sense of touch. They have sensory cells distributed across their bodies that allow them to feel vibrations and changes in water pressure.
- Taste – Sharks also have a sense of taste, although it is not as prominent as their other senses.
The taste buds of sharks are located inside their mouths and throats, allowing them to discern between different types of food.
The question of whether sharks like human blood has been thoroughly examined, and the evidence suggests that sharks are not particularly attracted to the scent of blood.
However, while they may investigate the scent of blood out of curiosity or hunger, shark attacks on humans are extremely rare and usually a case of mistaken identity.