Challenges of an Apex Predator: The Great White Shark and our Ecosystem

Yesterday, I asked the question: which is the most frightening apex predator? The choices that I brought to the discussion were a great white shark or a human being. My thoughts lean towards human beings being the more dangerous of the two groups. In this post, I want to take the time to introduce the great white shark as an unique and beautiful creation, look at the differences between great white sharks and the other shark family members, and how the great white shark interacts with his environment and its inhabitants.

The members of the shark family are different from most other animals that live in the ocean due to their lack of a bony skeleton. Instead, sharks have a cartilaginous skeleton which gives them an advantage of a lighter weight physique. They have jaws that do not attach to their cranium which allows greater range of movement, teeth that are continuously replaced with the advantage of always having a strong weapon for catching prey, and their bodies and skin are developed for easy movement and speed in water. One disadvantage to not having bones is that the shark is not able to swim backwards- only forwards or to the side. Sharks also have the disadvantage that they have problems with buoyancy- a very fatty liver helps to keep them from sinking, but most sharks need to stay in constant motion so that they do not sink, and also to breathe as they need the water to move through their mouths to their gills so that they can breathe.

Sharks have a very long history on our earth. Sharks are believed to go back hundreds of millions of years and modern shark ancestors are believed to have begun around 100 million years ago. One of the great whites well known close ancestors was C. Megalodon, a shark that is believed to have gained lengths of 100 feet (In fact the great white is C. Megalodon's only surviving close relative although this is relationship is not agreed upon by all scientists and is a subject for much debate.) The great white shark in many ways physically looks like its past ancestor -whether they have behavior in common is still debated by scientists.

The great white shark has a few traits or behaviors that are unique in comparison to its other shark cousins. The great white shark can hold its head out of the water- out of hundreds of sharks, only one other shark can do so the same. The great white shark wins hand down on the claim of being the world's largest predatory fish. Great white sharks are also different from other sharks in terms of their fins, conical nose, and distinctive coloring. It is one of less than a handful of sharks that have been documented to attack humans – not that that is a great distinction!

The great white shark is a very important and vital part of the ocean's ecosystem. As an apex predator, they feed on a large number of invertebrate and vertebrate animals - examples are sea lions, seals, other sharks, rays, whales, small cetaceans, etc... As an adaptable animal, its diet can and does change with its environment so studying the shark's feeding habits are difficult at best. Because the great white shark is the 'top dog' of the seas so to speak, its importance to the oceans and to our world cannot be overstated. If the great white shark was to become extinct, it could lead to huge increases in its prey populations which in turn will cause changes in many other animal and plant populations. And unfortunately, this shark is currently endangered and runs a real risk of extinction in the future.

So, you ask, why have I possibly bored you with all this information about a animal that at best you have never seen and know very little about? Why defend a creature that seems to have so few redeeming characteristics to the majority of the human population? A few ideas are listed above. In the last installment to this post, I hope to answer this question fully and also hope that I can instill a sense of concern if not urgency for the endangered species of the world which struggle and for the sanctity of life that I believe in.

Which is the Most Frightening Apex Predator: The Great White Shark or Man?

(This post is part of a three part series which will attempt to address our relationship with sharks, why we fear them, how we can save them, and why we should!

Apex Predator- (also known as alpha, super-, or top-level predators) are predators that have virtually no predators of their own, residing at the top of their food chain. Apex predator species are often at the end of long food chains, where they have a crucial role in maintaining the health of ecosystems.

In the last month, there have been two very highly publicized and sensationalized shark attack/ fatalities. In Cape Town, South Africa on January 12th, a man named Lloyd Skinner was killed by a 'dinosaur sized' or 'gigantic' shark that is believed to have been a great white shark. In Stuart, Florida on February 3rd, a kite surfer named Stephen Howard Schafer died from injuries sustained when he was attacked by a shark that was originally reported to be a 'great white' shark who attacked in a 'multiple shark attack' or from 'a herd of sharks'.

Sharks are in the mind of most human beings to be the ultimate predator. It you ask people what animals they are frightened off, very few off the top of their heads name lions, crocodiles, etc... Sharks are the most frequently mentioned and great white sharks are the most accused and feared. Why this fact is seems to have many factors. Some factors are education/history (except for brief moments in some biology classes, the tales were hear from the past are not positive toward sharks), biology or natural survival instinct (fear of the unknown, the dark, 'monsters' and being eaten alive are all biologically ingrained fears), media (sharks are routinely stereotyped and villianized in most media sources and these sites sometimes actively push humans toward fear and loathing – remember “Jaws”) and control (as human beings we are fascinated and repulsed by things that we cannot control or will not bend to our will.) So, as long as humans have used the sea, sharks and man have had the potential to collide with negative results for either party.

So I ask the question: Who is most dangerous... the great white shark or man? To me, this question is so much more complicated that it sounds. Any apex predator is dangerous and certainly you will not find me trying to make an argument that sharks are not potentially dangerous to us. Sharks have instincts, are carnivores, and roam the seas looking for food and sometimes to breed. They have large teeth, are very 'curious' creatures, can sense even minute amounts of blood in their 'air' and are frankly quite formidable in the sense that they can move quickly and silently in their environment. The are also the larges predatory fish in the sea. The idea that they have flexible territories so more than one shark can exist (and do) in coastal areas adds to the risk. A great white shark is a predator and while humans are not their preferred food, shark attack numbers go up as more and more people enter a sharks environment. After all, we as humans need to remember that the seas are a shark's home and its domain- we are the visitors.

Humans are also an apex predator. We rule the land we inhabit. Other animals may question this fact, but few human beings could disagree with this assessment. We move other animals out of their habitats and take the space for ourselves. Humans mold the land into the image and shape they want for food, transportation, habitation. We move rivers, carve mountains, and sometimes change the entire shape and ecosystem of an area with man made inventions such as a water dam. We kill animals who live in our territories deliberately if they cause us difficulties or annoyance, and unintentionally by our daily activities. Land is our home territory and over the years (with few exceptions) we remind all others living that we are the supreme apex predator.

I believe that human beings are a much more dangerous predator than the shark for three basic reasons. The first is that the great white shark may change the borders of its personal territory, but as a species, it never pushes past certain borders and certainly has never found the way to leave it's environment and continue to live. The shark, no matter how it is feared, cannot leave the ocean so we can control how often we put ourselves into their territory. However, human beings have taken over may portions of territory previously denied to us- the air and the sea for starters. The shark has his tools or weapons- they have changed little over thousands of years. Our weapons have changed greatly over the years and allow us to kill the shark with very little risk to our own personal safety. Another concern is that great white sharks are not interested in us as human beings or predators. Human beings are too bony for a good meal and unpredictable. So while a shark may bite us out of confusion or curiosity, usually one bite is enough for the shark to find the human unappetizing and he is off to hunt something else. Humans on the other hand, are perfectly willing to hunt sharks for food or simply for 'sport'. We will carefully bait them and after tricking them into a trap, we will kill them as trophies or simply for 'a good weekend'. The last reason I believe that humans are the most dangerous predator is that we seem to be one of the few predators that is not on the 'endangered species' list. As human politicians and scientists debate global warming and growing populations, biologists and marine scientists watch with growing alarm at the rising number of animals that need to be listed as endangered or even extinct. While their voices are not quite unanimous, their voices cry that we are the animal that is causing the harm.

So this is my opinion... What is yours? Which apex predator do you think is more dangerous... us or them?