Shark Attacks: Why Do Sharks Enter Fresh Water?

Hollywood has dramatized many shark films to depict sharks as bloodthirsty, flesh tearing, soulless predators that roam the seas scouring for juicy, innocent humans to feast on. Bull sharks are known to be one of the most aggressive sharks; however, shark attacks are extremely rare averaging only sixteen per year (National Geographic News). Most of these attacks are also due to the fact that most sharks have poor eyesight and easily get confused between humans and other ocean wildlife. Sharks are much more than sea monsters slashing through the water. They are beautiful, fascinating creatures that have many interesting characteristics. The bull shark, in particular, has learned to adapt from salt water to fresh water. This amazing animal can

Without salt the shark's cells rupture, which leads to bloating and death. This is why most sharks cannot enter fresh water, because their internal salt levels would become diluted causing their cells to burst (National Geographic News). Bull sharks are unique because they can adapt their process of osmoregulation in order to adapt to the fresh water environment. When bull sharks are in salt water, they contain a high concentration of urea, and other solvents which help balance out concentration of salt (jeb.boilogist.org). They expel large amounts of salt in their bloodstream through urination (shark saver.org). When bull sharks are in freshwater environments they adapt their process of osmoregulation. Their kidneys can be gradually adjusted to control salt conservation based on the salinity of their surroundings. The kidneys and special glands near their tails recycle the salt within their bodies. They remove more urea from the bloodstream through urination when in freshwater, essentially reversing the regular marine shark method of osmoregultion (jeb.boilogist.org). This adaption allows bull sharks to live in both freshwater and

Their bodies have learned to adapt to its surroundings in order to survive. Despite their appetite and aggressive reputation bull sharks can be docile in certain environments. In the aqua clear waters of the Bahamas, divers regularly interact with crowds of bull sharks (National Geographic News). In Genesis 1:21 it says, "And God created great whales, and every living creature that moveth, which the waters brought forth abundantly, after their kind, and every winged fowl after his kind: and God saw that [it was] good." God created everything with a specific purpose. Bull sharks and all sharks in general are vital to a healthy marine ecosystem. They keep food webs in balance, keep prey population healthy, help clean up the other decomposing animals in the ocean, and keep sea grass beds and other vital habitats healthy (Shark saver.org). So even though they are thought to have an intimidating reputation, they have beauty, detail, and complex processes that ensure the survival a healthy ecosystem. Bull sharks are remarkable creatures that seem to defy normal living