All about Sharks
“He’s Just Misunderstood Is All”
As a dive instructor in the tropics I am asked on a nearly daily basis: “Are there sharks in the water?” to which I reply: “Yes, but they are small and harmless”, which immediately invokes the response: “But what if they get angry, or are hungry, or I intrude on their territory, or they have just lost their winning lottery ticket and are angry and try to KILL MEEEEEEE??!!!”
So, for all those super-duper nervous types out there I implore you to get better informed about this must misunderstood animal. Look at the facts and arm yourself with knowledge, because ignorance about a subject is what leads people to make malformed opinions about things. This is a very bad trait in SCUBA diving because you need to keep a cool head when your down there. The fastest way I know of blasting through your air is to simply focus on the wrong things and get yourself worked up over nothing, anxiety leads to stress which leads to elevated physiological responses such as adrenaline release and increased breathing. What I’m saying here is there is no point in ruining a great dive by imagining Jaws coming at you from all directions, learn the basics, understand sharks and you will loose the fear.
And because I’m such a nice guy, I’ve compiled a list of interesting, surprising and enlightening facts about sharks which I’ve split into topics. I’ve intentionally included a list of facts relating to shark attacks to assuage your irrational fears. I’ve also highlighted my favorite facts by italicising them, some of them are really amazing!
General Information, Facts And Odd Behavior
Sharks do cool stuff and have been around for ages, so I felt we should start our shark tour with a little familiarization with the species as a whole.
Sharks have been around for about 400 million years – long before dinosaurs even existed.
Sharks will often eat other sharks.
The Whale Shark is the worlds biggest Shark and fish. It can reach the same length as one and a half buses!
The Mako Shark is known to leap clear out of the water, and sometimes into boats.
In Germany and Japan, shark skin was used on sword handles for a non-slip grip. (A shark sword is gonna make you the baddest guy on the block for sure!)
There are 355 confirmed species of Shark ranging in length from 15cm to 15 meters.
A fossil of a “cladoelache” is determined to be the oldest known ancestor of the Sharks. It is 350 million years old.
The Swell Shark, found in New Zealand, barks like a dog.
The smallest shark is the spined pygmy shark that grows to around 15cm long, the same size as a chocolate bar.
Tiger sharks have such a varied diet they have earned the nickname ‘garbage can sharks’. They will eat almost anything they encounter in the water: bony fish, sharks, seabirds, turtles, lobsters, cats, dogs, number plates and octopuses.
The biggest sharks in the sea, the whale shark and the basking shark, are completely harmless. They feed on small shrimps that they strain from the water using their gills while swimming along with their huge mouths open.
There is a reason that sharks are so widely revered, feared and studied – their anatomy is a marvel of natural engineering, they are truly magnificent creatures!
Sharks have the most powerful jaws on the planet.
Sharks never run out of teeth – when one is lost another spins forward from the rows of backup teeth.
A shark may use over 30,000 teeth during its life.
Two-thirds of a Sharks brain is dedicated to the sense of smell. Sometimes a shark is called “a swimming nose”, for its great sense of smell. Sharks can easily detect prey that is in the sand, as well as at night.
A shark also has a remarkable sensitivity to vibrations in the water. It can feel the movements made by other animals that are hundreds of feet away. They can hear sounds from thousands of feet away. Sharks can tell the direction from where the sound is coming from, too.
Most species of sharks can swim up to 20-40 miles per hour. A Mako Shark has been recorded at more than 60 miles per hour.
A shark has three types of fins. They have two dorsal fins on their back, one fin beneath their body, called the pectoral fin (not all species have it), and the caudal fin is the tail.
Sharks are fishes, but unlike most fish their skeletons are made of cartilage, which is lighter and more flexible than bone.
Although fishes are generally cold blooded, some fast-swimming sharks maintain a body temperature higher than the sea water around them.
Sharks cannot hover in the water like a goldfish and they must keep swimming forward to stop themselves sinking. Some sharks, however, habitually lie on the bottom of the sea.
Shark skins are covered in tiny teeth called denticles. This helps them swim more efficiently. Speedo worked with scientists at the Museum to develop a high performance swimsuit that copied this idea from sharks.
Sharks have very different types of teeth depending on their diet. The grinding pavement teeth of the Port Jackson shark are used to crush sea urchins, invertebrates and small fish and the pointed teeth of the kitefin shark help it to eat fish.
Sharks aren’t just normal fish, they have different styles of reproduction too. The final fact in this section literally had me gasping “wow” out loud!
Baby Sharks are called pups.
Sharks do not care for their babies after they are born.
Some sharks can’t reproduce until the age of 20 or above.
Most sharks have six to twelve babies at a time, but the Hammerhead and Tiger Shark can have as many as 40 babies at a time.
Some sharks produce live young while others lay special egg-cases on the sea bed.
The sand tiger shark pups developing inside the mother will eat each other until just one survives. This is called intra-uterine cannibalism. Survival of the fittest…in the womb!
Ok, so here’s the really important part; you’ve just read how sharks are the fiercest predators in the sea and how they are basically unstoppable forces of nature, now you should read why they are simply not that dangerous. Bear in mind, any wild animal is a danger, and that all animals should be treated with respect so don’t take this next section as an excuse to go abusing sharks…it simply means that you can go and dive with them, and enjoy their grace and power:
The most harmless sharks tend to be the largest, such as the Basking Shark, the Whale Shark and the Megamouth Shark.
There are more reported attacks on humans by Great White Sharks than any other type of shark.
Great White Sharks can go up to three months without eating.
More people are killed each year by pigs than by Sharks.
Sharks attack around 50 people each year worldwide, with perhaps 8-12 fatalities, according to data compiled in the International Shark Attack File (ISAF). To put that into context; think how many people go swimming in the sea off of one busy beach in one day… it would be hundreds, maybe thousands. Now think of how many beaches there are in one country, again hundreds. Now think of how many countries have beaches…then include divers, surfers, fishermen along with those swimmers and you are looking at more than a hundred million people that use the sea a year and of those people, around fifty people are harmed a year?! It’s hardly likely is it? This is the occasion where you have to let logic prevail over Hollywood, you just aren’t that likely to get attacked by sharks.
Of the 460 different kinds of shark in the world, only three occasionally attack humans, most feed on shellfish and small fishes. Crocodiles, dogs and pigs kill more people each year than sharks do.
Almost any shark 1.8 m or longer is a potential danger, but three species have been identified repeatedly in attacks: the Great white, Tiger, and Bull sharks. All three are found worldwide, reach large sizes and eat large prey such as marine mammals or sea turtles.
More attacks on swimmers, free divers, scuba divers, surfers and boats have been reported for the great white shark than for any other species. However, some 80% of all shark attacks probably occur in the tropics and subtropics, where other shark species dominate and Great white sharks are relatively rare.
Humans kill up to a hundred million sharks every year through fishing activities.
I put that last one in bold at the end there because that’s the only fact that I feel you must take away with you, sharks kill around ten people a year out of self defence and we kill up to a hundred million of them, that hardly seems fair to me. So, when you are next getting anxiety pangs about whether you will be attacked by sharks or not, just remember the sad and depressing fact that there is but a fraction of the animals left in the wild, so you probably won’t be lucky enough to see one…
Do you have an amazing fact about sharks that you love to share with folks on the boat? Have you ever dived with sharks, and if so what was it like? Are you still afraid of sharks, why? Please share your thoughts and feeling on the subject by using the comment section bellow.
Happy (well-informed) Bubbles!
By Jamie Campbell