Post created by Ian
According to the article, “Senses” by the State of Hawaii, a shark’s most acute sense is the sense of hearing. Most people that have some knowledge about sharks have the common misconception that sharks can smell a single drop of blood from up to a mile away. Although that’s a myth, sharks do have many other advantages over the rest of marine organisms such as well-developed night vision, improved sense of taste, and many others. The article talks about how sharks tend to have special receptors like electroreceptors and lateral lines which allow the shark to have two other senses.
As you can see, sharks have a wide-ranging variety of developed senses, but one that excels from the rest is hearing. The explanation behind this is that sound travels faster and farther in water than an air, on top of that sharks have a specialized internal ear structure that is much more sensitive than humans, allowing them to hear their prey from substantial distances. The distances can go up to 800 feet, around the size of two football fields combined. These cartilaginous fishes also relate to humans in another way because both species inner ear controls the body’s balance. The article also talks about how sharks appear to hear better in ranges in between 20 and 300 Hz and sounds below 40 Hz seem to captivate them which is convenient because struggling fish produce around the same range of Hz.
There’s no doubt that sharks most developed sense is hearing but they also have an exceptional sense of smell. Although they roughly have the same sensitivity as other fish, it is still enough to make them feared predators. Shark’s nostrils do not connect to their throat, meaning that as sharks swim there is water that flows through one specific side of the nostril and nasal sac, and finally out. In addition, sharks have very sensitive olfactory receptors that allow them to detect smells other organisms can’t. For instance, the account states that, “Blacktip sharks have been reported to detect fish flesh diluted to one part per 10 billion parts of seawater. As with sound, and shark’s ability to detect depends on the magnitude of the source, its distance, and dispersal. In some test sharks were able to detect smells at distances of several hundred yards” (State of Hawai’i, Hawai’i Sharks).
Another important aspect to shark’s senses is the lateral line. This system is basically a sequence of fluid-filled canals under the shark’s skin, and it contains specified pores that provide direct connection to the surrounding environment, in this case water. Furthermore, the lateral line system detects flow of water under the shark skin and low frequency pressure. The water movement causes the pressure to change (mostly when there’s nearby prey swimming). The different types of vibrations also known as “acoustic-lateralis system” and pressure change allow the shark to detect things as close by prey or simple movement changes in the water.
Another thing from the article that caught my attention was the shark’s sense of sight. Sharks and humans have similar eye structure, but they differ in the focus mechanism since the lens shape doesn’t change. Some sharks are able to see color due to the rods and cones in the retina, but the impressive thing is that in some experiments, sharks were able to see targets up to thirty yards in clear water. The article explains how reflective and high-contrast objects are not difficult for sharks to see, but the precise shapes they see are still unknown.
Besides, sharks have another sense that is distinctive to their species, and that is to detect weak electric fields that bodies of living organisms generate. Sensory organs such as the ampullae of Lorenzini allow these fields to be detected. Finally, the article concludes with the electroreceptors that help sharks locate their prey before they bite it and the touch receptors located from their tongue to the rest of their body. In conclusion, Sharks have a variety of well-developed senses that make them so crucial to the marine ecosystem and fearful predators. From being able to hear and smell at considerable distances to using their lateral line system to detect prey and movement.
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