Shark senses and behaviors

Shark senses and behaviors

“He perceives the slightest pressure wave from my smallest movement, analyzes every change in acidity or in the vaguest of odors, and he will never allow himself to be surprised by abrupt movement.” (Cousteau.)

hark Senses

Sharks’ senses allow them to maneuver through water, hunt prey, and sense danger. Like most other creatures, sharks possess the five common senses of vision, hearing, taste, smell, and touch or feeling. However, they also have another very unique sense known as electro-sense.


Electro-sensitivity is the ability to detect pressure waves in the water (similar to vibrations in the air) caused by the muscle activity, or movement, of other animals in the water, as well as to navigate through the water using magnetic fields. “Because all living things produce weak electrical fields, sharks are able to detect these fields in the 0-8 Hz range with electrical field differences of as small as 5 billionths of a volt per centimeter.” (citation) They are able to pick up on these currents and pressure waves using a sensory organ just under the skin of their snout called the ampullae of Lorenzini. The ampullae are small clusters under the skin that are connected by jelly-filled tubes to the pores on the surface of the skin. The lateral line, a common sensory organ of marine animals, also assists in the detection of movement as well as hearing low-pitched sounds in the water. The lateral line consists of two fluid-filled canals running on either side of the shark’s body head to tail.


Unlike the shark’ sense of smell, their electro-sense is limited to only several feet in front of their snouts. However, the sense is very acute in that it can pick up on even the smallest of vibrations within range, as implied by the observation made by Jacques-Yves Cousteau, an underwater explorer, stated above.


Sharks have a very acute sense of hearing. Their ears are not visible, being located inside the head. The inner ear is connected to the surrounding water by a series of ducts and canals.

Sharks’ auditory sense is very sensitive to hearing low-pitched sounds with a range of hearing that goes much lower than that of a human. This trait is very useful in helping them find prey. Dying or struggling fish give off these low-pitched sounds and vibration thus attracting the shark to them. Because sound travels four times faster in water than it does in air, sharks can detect these sounds from miles away.Several experiments were conducted on this theory by Don Nelson. He and his team recorded and modified—by taking out the high frequencies and white noise—low drumming sounds and played them on underwater speakers in attempts to discover what sounds would attract the sharks. As it turned out, sharks only appeared when these drumming sounds were played. In one instance, a shark was approximately half a mile away from the speaker and upon hearing the noise, immediately turned toward the sound at rapid speed. Another shark came up from directly below the speaker, bit it and dragged it straight back downward. After having completed this experiment, Nelson attempted for an opposite effect. Instead of low-frequency noises, he recorded and played high frequencies. This experiment did, in fact, have the opposite effect on the sharks. Played in a swarm of sharks, the sound repelled the creatures and they immediately dispersed. (cite)


Sharks’ vision does not pick up as much detail as the shark’s other senses, but it is still very developed. Like humans, sharks can widen or tighten their pupils based on light quantity and intensity in order to control intake of light and dark. Instead of focusing on details, sharks use their vision to discern between differences in light quantities or between light and darkness. Many sharks possess, behind the retina in their eyes, a mechanism called the tapetum lucidem. This mechanism has the ability to amplify light and also to provide the shark with nocturnal vision.


Sharks’ sense of taste, or their gustatory sense, can also be called their sense of touch. Sharks not only taste with their mouths, but also with their skin. Simply by making bodily contact, sharks can taste the gustatorial papille of an object or animal with the sensorial cells in their skin. The olfactory sense that sharks have, also called their sense of smell, is extremely acute. A shark can smell one unit of blood in 100 million units of water. Even the slightest bleeding from a scrape or cut on a person or another animal can attract a shark.

hark Behavior

Behavior of sharks varies greatly within species, as do their diets. Sharks mostly eat tiny fish and marine animals. Some species are aggressive while others are very passive and fairly harmless.

Basic Activity

Sharks are believed to have daily activity rhythms in which they are most active during the twilight and dark hours.

Many scientists have developed a common misconception of sharks in that they have to keep moving constantly in order to keep breathing. This idea is based on the fact that sharks’ muscles are very weak and cannot adequately move their gills enough in order to pump the water through them. Sharks have five to seven gill slits as opposed to one like most bony fish. They also do not have the complex skeletal structure and the bony plate known as the operculum covering their gill slits that both assist the bony fish in the respiratory process. However, the assumption that sharks must be constantly moving is completely false. Some species of sharks—the carpet sharks and angel sharks—have adapted to this disadvantage and have developed stronger throat and gill muscles than most other sharks, which allows them to spend much of their time being stationary. Bottom dwelling sharks also have mechanisms called spiracles, which act as respiratory organs in their bodies.Not only can these few species of sharks breathe while stationary, though. Sharks sometimes use current from the ocean to pump the water through their gills while stationary. Also, In 1969, “sleeping sharks,” as they were named, were discovered by a diver resting in a series of caves off the Yucatan Peninsula. Later, Dr. Eugene Clark took his National Geographic team to investigate the discovery and found that the caves contained a higher level of oxygen than normal caused by fresh water seeping into the caves. This extra oxygen helps the sharks to breathe with greater ease.

ocial interaction

Sharks are generally asocial creatures. However, there are some exceptions such as hammerhead shark traveling in schools.


When sharks circle, it is to get a scope of the creature that they are encountering. This does not mean that they are readying themselves to feed on the animal, but merely that they are curious to observe the animal. They will not take the risk a surprise attack. They want to know if there is any possible danger in their environment.

ymbiotic Relationships

Sharks have symbiotic relationships with several small marine animals that accompany them for various reasons. Several species of small fish clean debris and waste off the shark. Another help to sharks is the Remora, and Echeneidae, that eats parasites off the shark. Parasites that commonly live on sharks include flatworms and copepods.

Prey and Eating Habits


Sharks do not tend to be very selective eaters. Their diets generally include molluscs, crustaceans, fish, marine animals, and others sharks. Some sharks do have preferences, however, and tend to lean more towards particular animals. For example, hammerheads tend to favor stingrays as prey.

Methods of Attack

Eating methods very greatly between species. Most use their teeth as the primary tool in an attack because sharks have weak jaw muscles and lack a strong jawbone and will often lose teeth in an attack because of the intensity of their bite, but can grow them back within 8 days, depending on the species. Because of the shortness of the jaw, the bite is very powerful.

Other sharks a filter feeders. These sharks scoop the water with their mouths open to envelope their prey inside their gaping jaws. Whale and Basking Sharks are such feeders. The Whale Shark uses a series of cartilaginous rods between its gill slits to filter plankton as it scoops.

In an attack, the shark uses, first, its lower teeth to puncture and hold the prey in prey and follow with using the upper teeth to slice the prey. Several bottom feeders, however, will use their upper teeth to pick up prey.On some occasions, sharks will actually swallow prey whole once it has captured it.

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