The Top 5 Reasons Sharks Rule – A Shark Week SpecialAugust 4, 2011 at 9:24 am | Posted in Humor, Miscellaneous, Regular Feature, Science News | 116 Comments
Tags: Shark week
This week Science Thursday happens to be the Thursday of “Shark Week” as ordained by the Discovery Channel. How basic cable stations get to declare an entire week dedicated to a single animal, I don’t know. In the case of shark week, I don’t care.
Why? Because sharks are the BAMF’s (umm… Biggest And Meanest Fish?) of the sea. When you go swimming at the beach and see the lifeguard running toward the water, you don’t suddenly strain to hear if he is yelling at some teenagers for excessive horseplay. You are listening for one word. “SHARK!” That lifeguard could be yelling at you that the doctor called and said you have a brain tumor and it would be a relief, as long as he wasn’t yelling “SHARK!”
Sharks are nature’s perfect biological murder machine. They are the Pac Man of the sea and everything else in the ocean is an energy dot. From their flesh shredding face daggers to a digestive system that can pass a license plate they are built for one thing, kill it and eat it.
So without further preamble I give you:
The Top 5 Reasons Sharks Rule
5. Their Sense of Smell
A shark’s sense of smell is definitely one of its most outstanding attributes. As the shark swims, water flows through two forward facing nostrils, positioned along the sides of the snout. The water enters the nasal passage and moves past folds of skin covered with sensory cells.
These sensitive cells can detect even the slightest traces of blood in the water. A great white shark can detect a single drop of blood in an Olympic-size swimming pool. Most sharks can detect blood and other animal odors from many miles away.
We humans, on the other hand, rely largely on our vision to process our surroundings. In the murky depths of an ocean full of sharks that becomes the aquatic equivalent of playing “Blind Man’s Bluff” in a minefield. One of these beasts could be fifteen feet away with it’s triple row mouth full of razor sharp limb cleavers wide open and ready to amputate your pelvis to get to the chewy center in your innards, and you would never know he was there unless you brought your own cello player.
I don’t mean longevity as in, “sharks live long lives,” although they certainly do. While many shark species live an average of 30-40 years, some species can live much longer. The Spiny Dogfish Shark has been known to live for as long as 100 years, as has the Great White. Some Whale Sharks have lived for an astounding 150 years. To put that in perspective, it is possible there is a whale shark somewhere in the world right now, dying of old age, that came into existence somewhere about the time of the beginning of the Civil War. So they are a long lived species.
When I talk about longevity though, I don’t mean an individual shark’s lifespan but rather how long they’ve been in existence as a species.
There’s no doubt that sharks are one of the most feared creatures on Earth. They are also one of the most enduring. The oldest shark fossils found by marine biologists to date are from more than 300 million years ago. To put that in perspective, the age of sharks predates the the age of the dinosaurs. The sharks however, laugh at meteor impacts and ice ages.
A few existing shark species, such as the horn shark, have kept the same basic physical characteristics for more than 150 million years. Scientists attribute this remarkable longevity to the shark’s superior physiological developments. Sharks are outfitted with several special characteristics that make them highly effective, both as hunters and survivors.
So let’s do the math and a little logic assessment of what that means. Mankind has been around for roughly 150,000 years. Sharks have been around for roughly 300,000,000 years. That’s a three and eight kriffin’ zeroes. That is roughly two thousand more times than the entirety of human existence.
Now while mankind has achieved much in its brief tenure as the dominant species on land, such as space flight, computers, and processed room temperature cheese spread in an aerosol can; the sharks have been focused for two thousand times that long on one thing. Killing. And they’ve gotten very very good at it.
3. Their Skeletons
Jellyfish aside, pretty much every animal on the planet has some sort of skeleton. Be it fish or fowl, reptile or primate, insect or invertebrate, almost all manner of macroscopic life has a frame of some sort on which the rest of it is supported. So what is so unique about a shark’s?
Sharks have skeletons made entirely of cartilage. That is the same pliable, highly flexible substance your nose and ear bones are really made of. Cartilage is strong and sturdy but it has a much lower density than real bone. This material keeps sharks relatively lightweight, so they don’t sink in the ocean and they don’t need an air bladder like other fish.
So how does this marvelous, pliable skeleton make sharks scarier? Consider if you will, all the torture and torment the open sea can dish out. All the storms and tsunamis and prey vs. prey action. All the whirlpools and underground volcanoes and a million other ways to die. Now imagine being a one ton great white killing machine of a shark jumping into a feeding frenzy knowing you will bend but not break. It just isn’t fair I tell ya.
2. You Can’t Sneak Up On Them
As if the insane, borderline superpower sense of smell, the eons of evolution, and the pocket comb pliable skeleton weren’t enough to make an encounter with a shark a ridiculously one sided affair for anyone packing anything less than an eight gauge titanium cage and an 1800 psi spear gun, there are a few other advantages to being the shark in the “man meets shark” scenario. One of which is, you can’t sneak up on them. The big jerks always know you’re there. How? I thought you’d never ask. They actually have a couple of extra senses that we the shaved primates of the land don’t enjoy.
The first is brought about because sharks have hundreds of pores near their snouts know as the ampullae of Lorenzini and it provides the shark with a sense known as electroreception. Simply put it means that sharks can sense the electrical currents all living things give off when the move. Every time you move any muscle in your body, you are giving off an electrical current. Even at rest, anything with a heartbeat will give off a mild electrical charge. Open air doesn’t conduct those electrical charges very well so land species rarely develop this talent. Salt water is a marvelous conductor of electricity however and so with the three hundred million years the sharks had to play around with the program, they came up with a way to sense even the slightest current in the water around them.
What it means is, even if for some reason they couldn’t smell you, they would still know you were there, hiding behind that reef and quaking in your strap on fins. You could bury yourself in the mud and hold your breath and they would know precisely where to dig for a tasty treat. I would imagine it to be a bit of an Easter egg hunt for them. A good bit o’ fun for the whole sharkin’ family.
The other extra sense the shark gets to ensure you have nowhere to hide, is known as the shark’s lateral line. The lateral line is basically a set of tubes just under the shark’s skin. The two main tubes run on both sides of the body, from the shark’s head all the way to its tail. Water flows into these main tubes through pores on the skin’s surface. The insides of the main tubes are lined with hair-like protrusions, which are connected to sensory cells. When something comes near the shark, the water running through the lateral line moves back and forth. This stimulates the sensory cells, alerting the shark to any potential prey or predators in the area.
So essentially, sharks have seven senses. The can see, smell, hear, taste and touch, but they can also detect EM waves and unusual water movements. There is literally nowhere you could go while in their domain that they wouldn’t know you were. That is scary.
1. The TEETH !
Time to talk about the teeth! Sharks have the most amazing choppers ever devised by nature and are unparallelled in the animal kingdom. While the heading says “The TEETH”, it is impossible to discuss a shark’s teeth without first talking about their (for lack of a better term) jaws. You see, unlike the jaw of most animals (humans included) the shark’s upper jaw isn’t part of its skull. It is hinged to the skull but can be dislocated and lunged forward towards the shark’s prey in order to increase it’s bite radius. So it seems the sharks used the three hundred million years to make some serious design improvements.
How hard can those fantastic jaws clamp down? Why an amazing… 27 pounds of pressure. That’s right, one of the hardest biting sharks in existence is the dusky shark and it only bites down with 27 pounds of pressure. Despite the shmancy dislocating jawbone, it only bites down with 27 pounds of pressure. It’s more than enough, because that finally brings us to the teeth.
Now that we know how the jaw works it begs the question, “If the jaw is so weak, how does it do so much damage?” The answer of course is the triple to quintuple row of razor sharp, serrated, 2 to 3 inch teeth. A shark never runs out of teeth. It has as many as 3,000 teeth in its mouth at any given moment. When teeth are broken or fall out they are continually replaced for the entire life span of the fish.
The shark’s teeth act like a thousand mini guillotines as they are not designed to actually chew the prey so much as they are to instantly kill it so it can be swallowed whole. Only some bottom dwelling sharks have developed teeth designed for grinding open the shells of mollusks. The more active sharks need only the pure stabbing power of razor honed bone.
So There You Have It
The top 5 reasons sharks rule the oceans. This was clearly a humor piece as much as an informational one so I’d like to point out that there is a better chance of dying from a bee sting, getting hit by lightning, a drunk driver, an illegal handgun or choking on your Jello as there is of getting eaten by a shark. Of course I might go on to point out that for as long as those odds are, they go up substantially once you take your body and put it physically in the ocean. (To date there are no reports ever of a shark attack taking place in Kansas.) So should you decide to go where sharks live, I hope you will be aware that you may be the apple of your mom’s eye, but a shark just wants to shove an apple in your mouth and call you dinner. Have fun at the beach this summer.