How many senses do sharks have

This category also includes rays, sawfish, and skates. Their cartilaginous skeletons are much lighter than true bone and their large livers are full of low-density oils, both helping them to be buoyant.

Even though sharks don't have bones, they still can fossilize. As most sharks age, they deposit calcium salts in their skeletal cartilage to strengthen it. The dried jaws of a shark appear and feel heavy and solid; much like bone. These same minerals allow most shark skeletal systems to fossilize quite nicely. The teeth have enamel so they show up in the fossil record too. Most sharks can see well in dark lighted areas, have fantastic night vision, and can see colors.

This helps sharks see extremely well with little light. Sharks have small black spots near the nose, eyes, and mouth. These spots are the ampullae of Lorenzini — special electroreceptor organs that allow the shark to sense electromagnetic fields and temperature shifts in the ocean. Shark skin feels exactly like sandpaper because it is made up of tiny teeth-like structures called placoid scales, also known as dermal denticles.

These scales point towards the tail and help reduce friction from surrounding water when the shark swims. Nurse shark skin. Unlike most other sharks, nurse shark skin is fairly smooth.

When you flip a shark upside down they go into a trance like state called tonic immobility. This is the reason why you often see sawfish flipped over when our scientists are working on them in the water. Based on fossil scales found in Australia and the United States, scientists hypothesize sharks first appeared in the ocean around million years ago.

Vertebrae contain concentric pairs of opaque and translucent bands. Band pairs are counted like rings on a tree and then scientists assign an age to the shark based on the count.

Thus, if the vertebrae has 10 band pairs, it is assumed to be 10 years old. Recent studies, however, have shown that this assumption is not always correct. Researchers must therefore study each species and size class to determine how often the band pairs are deposited because the deposition rate may change over time. Determining the actual rate that the bands are deposited is called "validation". The blue shark displays a brilliant blue color on the upper portion of its body and is normally snowy white beneath.

As we learn more about ourselves, we come to understand that we can also sense such things as hunger, pain, and temperature. Most of us also claim a 'sense' of humor and style, although we recognize that this is not the same kind of sense as vision or hearing. As we learn more about the world around us, we learn that many animals have astoundingly acute senses, including several that we do not.

We humans are fascinated by these 'extra' senses. Inevitably, and despite the fact that many of them are beyond our experience or understanding, we want to know what these other senses detect and how well. Which brings us to sharks. Sharks are most famous for their phenomenal sense of smell. But, depending upon which book or authority one consults, sharks may have as many as 13 sensory systems - eight more than we are accustomed to.

But do they really? All sensory systems depend on receptor cells that respond to energy or chemicals in the environment by changing their electric charge.

This electric change, in turn, induces a series of events that signal the brain, where the environmental energy or chemical is interpreted. This capability is especially useful when hunting because if they listen to the low-frequency sounds produced by injured animals, they do not hesitate to follow the source until they reach the prey and feed on it. Thousands of dermal denticles cover the skin of sharks, but this feature does not prevent the loss of sensitivity. In fact, under the skin there are numerous nerve endings important for detecting surfaces and some species have a kind of beards around the mouth, necessary to stir the sand in the search for food.

Their teeth are another tool because their stretchy jaws allow a touch of identification. As their teeth have pressure-sensitive nerves, sharks often bite to test and determine whether or not what is touched is edible.

The sense of taste is not as developed as the other senses because it is not necessary to detect prey. However, sharks have taste buds all over the inside of the mouth and throat and not just on the tongue. Before they decide to eat something, they bite a piece and from the taste accept to eat it or to reject it if it is not part of its conventional diet. This sense is very sensitive to the fat contained in the meat tissues, since many sharks maintain a high-fat diet.

This sixth sense is unique and allows sharks to detect small electric fields generated by living beings, even if they are hidden or semi-buried in the sand. The organs responsible for electro-perception are the Ampullae of Lorenzini and each shark has hundreds and thousands of them scattered around the muzzle.