Sharks Had a Sixth Sense Before It Was Cool

Many myths and misconceptions surrounding sharks have been perpetuated throughout the last several decades. It seems something about their awe-inspiring and fascinating nature triggers the imagination, which then leads to stories, which eventually leads to fiction being intermingled with facts.

In the past, sharks have gotten an undeservingly nasty reputation. In recent times, however, we are seeing attitudes shift from fear of these animals to the appreciation of their beauty and nature. The mechanism that drives this positive change is most certainly the education of the public. The influx of shark related documentaries and shows in mainstream media have helped provide many with an understanding of these creatures that was previously missing. For this reason, I feel its important to share as much knowledge and information on these animals as we can. Education saves our sharks, and saving our sharks saves our oceans.

I’ve always been a shark lover, so when I chose to get my undergraduate degree in marine biology, I was thrilled with the new information I was learning about this truly magnificent species. After taking shark biology courses, I learned that there are so many astounding and interesting facts that Shark Week didn’t teach me.

Before we crack on to these shark facts, let’s discuss some of the myths you might have heard about sharks in your time.

Raise your hand if you've heard the phrase; "sharks can smell a drop of blood a mile away." I certainly have! Although this doesn't seem that hard to believe when you think about these apex predators and their evolutionary adaptations, this factoid is false for all shark species. Sharks certainly do have an impressive olfactory system far beyond the capabilities of you and me, however the maximum distance even the most advanced shark species could detect a drop of blood is around a quarter of a mile.

Another, and the most dangerous of all shark myths that you have probably heard is that sharks are man-eaters. While this theory has been disproven countless times in recent years, it's always worth mentioning that sharks are not evil. They do not wish to bring harm to human beings. Sharks are incredible creatures that deserve our love and respect.

Well, with that mildly annoying and preachy preface out of the way, let's talk about some interesting and surprising shark facts you might not have known!

Sharks don’t have scales.

This might come of as a surprise to those of us who know that sharks are fish. A fish without scales? How can that be? In place of scales, sharks are covered in dermal denticles. These structures are actually modified teeth, like the ones in our mouths. They are composed of a dentine surface surrounding a pulp cavity; and they act as armor. If you were to pet a shark from its tail to its head, it would had a sandpaper like feel due to these dermal denticles. Because of the way they are positioned, if you pet the shark from head to tail, it would feel smooth!

The largest sharks in the world feed on the smallest organisms in the ocean.

The two largest fish in the world are sharks. Unbelievably, both of these species are filter feeders! The whale shark and the basking shark, which grow to average sizes of 18-33 ft and 22-29 ft respectively, both filter thousands of gallons of water through their gill rakers each hour while feeding. They are slow-moving, gentle giants that feed on krill and other plankton. Despite their massive size, they are amazingly able to sustain themselves completely off of microorganisms.

Sharks can “puke” out their stomachs.

Yep. The entire thing. In a process known as gastric eversion, sharks essentially turn their stomachs inside out and expel them through their mouths. This allows them to clean their stomachs and free themselves of any indigestible or toxic matter. It's a rapid movement, and almost undetectable by the naked eye, but if you search this on the internet you'll be sure to find slow-motion videos that will astonish you. Out of everything I learned throughout my studies in the field of marine biology, this was one of the most surprising!

Sharks have a sixth sense.

Before M Night Shyamalan brought extra senses to the big screen, sharks had mastered one for their very survival. They have all the basics; sight, hearing, smell, touch, and taste. But, they have another that us mortals will never experience; electroreception. This feat of evolution allows sharks to detect electric pulses, which in turn allows them to sense the movement of prey. Living organisms emit electric pulses when they move. Injured organisms emit erratic electric pulses, which sharks pick up as well. Sharks are able to detect prey buried under sand and rocks thanks to this sense, and it is a key to their survival.

How is this possible? Have you ever seen a close up picture of a shark's head? If you have, you might have noticed the hundreds of little black dots all around their snout. No, the shark isn't suffering from a poor skin care routine. These dots are the Ampullae of Lorenzini, which are a network of highly specialized cells that enable this sense in sharks. These cells are electroreceptors, which detect electrical impulses from surrounding organisms. This allows the shark to hunt prey, even without seeing, smelling, or hearing it.

These are just a few surprising facts about sharks that you might not have known, but this barely scrapes the surface! I encourage anyone who enjoyed this article do continue research into sharks to find out more about what makes them so incredible!