How Does a Shark Hunt?
Sharks are apex predators.
They are on the top of the marine food chain and they hunt anything from fish and dolphins to seals and sea lions.
Don’t get confused here – sharks are not limited to only marine food. They will gladly kill and eat a swimming moose, elephant or YOU.
The exceptions are the planktivore species (a whale shark) that peacefully feed on plankton by sucking large amounts of water and filtrating the food through their long filaments.
Long range prey tracking
Sharks hunt using a combination of senses. First of all, they have an incredibly acute sense of smell. Studies have shown that a shark can smell a drop of blood from miles away. Their nostrils are located on the bottom side of the snout are used solely for smelling their prey.
Interesting fact. Shark’s strong sense of smell is used not only for hunting. There are evidences proving that shark males use their keen sense of smell to detect pheromones produced by females.
Hearing. Another long-range tool that helps sharks find their prey is their incredible hearing. Their ears are located inside of their heads and can sense the prey from 800 feet. Remember, underwater the sound travels faster and further than in the air. Sharks can hear sounds ranging from 10 hertz to 800 hertz, while humans can hear from 25 hertz to 16,000 hertz. For reference, the frequency of low E note in standard guitar tuning is 82.41 hertz (source).
Sharks hunting in mid-range
Once a shark gets closer to its prey it will use vision and the lateral line. Scientists believe that sharks may be color blind, however, just like cats, sharks can see much better in dark murky waters. It makes perfect evolutionary sense for a predator to have a good night vision. Sharks have their eyes located on the sides of the head for a wider view.
The lateral line (Mechanosense) helps sharks sense tiny vibrations in the water. The lateral line is located under the skin on the snout and alongside the body of the shark.
It’s important to keep in mind that sharks rely on a combination of senses. When fish, seals or other prey move through the water they leave a wake (turbulence) infused with their body’s smell. This is known as an “eddy”.
In close range
In close range sharks use Ampullae of Lorenzini or their electrosense. All living beings emit weak electric field. The head of the shark is full of small pores that amplify weak electrical signals and help the shark spot its prey even in complete darkness or if its hidden in the sand. Sharks are able to sense electrical fields only on a very short range – within 1 meter or so.
In such close range sharks will often bump their potential prey with their head or nose. This is a way to investigate what the shark is dealing with. A bump will often be followed by a bite, so swimmers and divers cannot let the shark bump them.
Taste is the final sense involved in deciding if the object will become the shark’s next meal or not. Despite a common belief, humans are not on top of shark’s menu. It is estimated that for every 1000 people who drown there is only one death from shark attack. The majority of sharks prefer fish or invertebrates, bigger species hunt marine mammals like seals or sea lions.
Interesting fact. Shark’s stomachs were know to contain remains of:
As well as:
- tin cans
- wrist watches
- engine blocks
- a bag with cash
- and many more
Interesting facts about sharks
- Some sharks can cycle through up to 35,000 teeth in their lifetimes
- Sharks have a nearly 360-degree field of vision
- Some sharks hunt along, while others (like scalloped hammerhead) hunt in schools
- Bamboo sharks don’t swim. They use four different fins to walk across the ocean floor
- Humans kill 100 million sharks a year. That means for every single person killed by a shark, humans kill 25 million sharks