Sharks

Just like spiders and snakes, sharks have a fascinating and repulsive effect on people. Fascinating because they are efficient hunters and repulsed due to their reputation as man-eaters. Notwithstanding the latter, many people will literally jump at the chance of being around them. That is, if the environment happens to be under control.

General Background

Thanks to television programs, there is a lot we’ve learned about sharks. We know that their skeletons are made of cartilage instead of bone, making them about half as light.

And while many creatures would welcome a light skeleton, the main drawback of cartilage is that it tends to dissolve instead of fossilize once it dies. This inability to turn into rock over time means that we rarely have prehistoric shark skeletons today. Fortunately, teeth do become fossilized so scientists use them to estimate the size of prehistoric sharks.

Based on fossilized teeth, the biggest shark is considered to be the Carcharodon Megalodon, or Meg for short. Some scientists estimate this shark could grow as long as 80 feet when it was alive 26 million years ago. With such a huge length, it might have been able to swallow an average adult standing up.

Speaking about teeth, we know that sharks have several rows of them. And instead of being fused to the jaw like the teeth of land mammals, they are imbedded in a shark’s gums. This makes it possible for any tooth that breaks off to be replaced by a new by easily sliding from another row. Furthermore, we also know that most shark teeth are serrated, making them much more effective at cutting up their food.

We also know that the skin of the shark is very tough. Instead of the typical scales of fish, the scales of sharks are composed of Dermal Denticles Being modified teeth, each tiny scale is hardened with a coating of enamel surrounding a pulpy core. Not only does it act like armor, their overlapping design allow a shark to slip through the water more easily.

When it comes to smell, some sharks can detect as little as one part per million of blood in seawater. More interesting is that they can actually hone in on the source of the blood through stereoscopic nostrils.

Shark eyes are quite different from other fish. The first difference is that some have eyelids but rarely blink because the water around them is enough to clean them. Some can even dilate their pupils like land creatures. A shark’s eyes are also designed to see much better in the dark waters of the sea and they can do so with stereoscopic vision.

Some species of sharks are extremely sensitive to the electrical impulses of other creatures. These impulses are felt whenever the muscles used for swimming, eating, and breathing. Sharks are so sensitive to these minute impulses, they can detect prey even if it is buried under sand.

Using their sense of smell and ability to detect electrical impulses allowed sharks to learn if there is injured or weak. The advantage of being able to target wounded or weak prey, means that a shark will not have to expend as much energy to catch it.

Finally, sharks do not have air bladders to keep them from sinking. They are dependent on their cartilage skeleton and liver, which contains shark oil, to help do this. This lack of buoyancy means that certain species of shark need to constantly keep moving because they cannot pump water through their gills like fish do. So if they rest too long at the bottom of the ocean, some species may end up suffocating.

No Natural Sighting

Thanks to the movie Jaws back in 1975, the biggest thing that strikes fear in the heart of every beachgoer may be the dorsal fin cutting through the surface of water.

While I have heard of attacks and come across the occasional video of underwater sightings, I have been fortunate enough not to see a single one at any of the beaches I have visited.

Perhaps the most story I have come across involves one about a handful of divers who encountered a shark while going through a wreckage. Since the shark stuck around, a decision was made to head to the surface. But as they ascended, the shark began to circle them, coming with each turn. A few seconds later, a big explosion was heard by everyone in the water. It turns out one of the divers had pulled out a hand gun and shot the shark.

Now before you swear never to go back into the water, I need to state that I have no recollection who told me this story all those years ago. I don’t even recall what part of the world it was supposed to be in.

For all I know, it could have been handed down to me by a friend who heard it from the friend of another friend. In addition to this, the shark in question might have started out as tiny fish and grew in length with every retelling of the story.

[I usually take discussions involving some alcohol with a grain of salt.]

I’m more inclined to believe the statistics presented by the Shark Attack website than this bar room story. And the good news is that for the year 2014 and up to the month of September, it lists absolutely zero injured, harassed, or fatal attacks in the Philippines. And since I haven’t seen any sharks in the decades I have visited the beach, I see no reason to stop enjoying the sun, sand, and sea in the country.

[One of our writers did enjoy swimming with the gentle Butanding, or Whale Shark, in Cebu though.]

Just to give you more of an idea, the Shark Attack website indicates that 49 persons were injured, 9 individuals were harassed, and 5 people died from shark attacks around the globe during the same time period.

Considering that there are eight billion people on Earth, this makes the percentage of shark attacks quite small. In fact, data compiled by the National Weather Service of the United States indicates that more people have died from lightning strikes than from shark attacks for 2014 as of this writing. Specifically, twenty four people have passed away due to lightning strikes in the United States alone versus the five fatalities of shark attacks worldwide.

Final Thoughts

Even if people have a fear of sharks, it seems that their fascination of these creatures still gets the best of them. And this it is probably this attraction that drives many aquariums around the world include sharks in their exhibits.

I, too, am not immune to their allure because when my wife and I visited Underwater World Singapore, it was the shark tanks that attracted me the most.

Unfortunately, over-fishing and fear are cutting down the numbers of sharks around the world. It has gotten so bad that I understand some species are in danger of becoming extinct. If we don’t address this problem, the only place where sharks may exist will be in aquariums.

So the next time you are swimming in a beach and happen to see a gray fin in Philippine waters, don’t panic; it could just be a dolphin or a Whale Shark. Check with the lifeguard on duty because they are in the best position to tell what is in the water and how to handle the situation. Do not start yelling because a stampede could result in injuries.

Just enjoy the sun, sand, and sea and worry more about the sharks on land than in the water because the kind that walks doesn’t look like it is in danger of becoming extinct.

Finally, you can check out more shark pictures at the Shark Photo Gallery at the Crazy About Pictures website.