Introduction to Sharks
There are more than 465 known species of sharks living in our oceans today. Sharks are an apex predator at or near the top of their marine food chains, and they regulate the populations of species below them. Research has shown that massive depletion of sharks has cascading effects throughout the ocean’s ecosystems.
Sharks belong to a family of fish that have skeletons made of cartilage, a tissue more flexible and lighter than bone. They breathe through a series of five to seven gill slits located on either side of their bodies. All sharks have multiple rows of teeth, and while they lose teeth on a regular basis, new teeth continue to grow in and replace those they lose.
Shark ‘skin’ is made up of a series of scales that act as an outer skeleton for easy movement and for saving energy in the water. The upper side of a shark is generally dark to blend in with the water from above and their undersides are white or lighter colored to blend in with the lighter surface of the sea from below. This helps to camouflage them from predators and prey.
In modern times, the shark is known as a predator that will attack at the sight of blood. However, this myth of sharks is not necessarily accurate. In fact, shark attacks were less than 20 a year in the late 1800s. It has not been until the last two decades that shark attacks have become a more known factor in various areas of the globe. But contrary to popular belief, only some sharks are dangerous to humans, for example, Tiger shark or Great white shark.
It has been found that these attacks are not because sharks are typical predators. Typically, they will occur because there is a territorial threat or disturbance that occurs in the sharks inhabited area. At other times, these attacks will be ones that are provoked by humans, causing the shark to try to keep a safe ground. Things such as spear fishing and eco-tourism are contributions to sharks that feel the need to attack. Even among these attacks, it is only certain species that will feel a threat and will respond. Others will simply move into a different territory.
Through this predator fish is an evolution that has led to a specific lifestyle with sharks. In every area of the ocean is a type of shark that has moved into their living space, becoming one of the most known ocean dwelling creatures.
Sharks are extremely intelligent creatures so it is no surprise to learn they have plenty of ways to engage in effective forms of communication. Yet sharks are generally loners so they aren’t in groups. This makes it harder to observe how they actually communicate with each other than with other animals that live in the water.
They have an amazing sense of hearing which is believed to be how they communicate most of the time. They can hear sounds at very low frequencies so a great deal of it won’t even be picked up during the observations. They can also use their senses that allow them to pick up vibrations and electrical currents from other sharks in the water with them.