The Case Against Giant Sharks

Does anyone remember when Shark Week used to be about sharks--the biology of sharks, the lifestyles of sharks, fun facts about sharks and the people who watch them? Well, those days are long gone: now we have made-up documentaries about giant prehistoric sharks like Megalodon and endlessly recycled exposes of humongous, mythical, 40-foot-long Great Whites that swallow other sharks practically whole. (Lest you think  Im unfairly picking on The Discovery Channel, bear in mind that no less an eminence than The Smithsonian Channel has aired dreck like Hunt for the Super Predator.) But before we go any further, heres an important caveat. There are, in fact, gigantic predators lurking beneath the oceans depths, some of which have only rarely been glimpsed by humans--the classic example being the Giant Squid, which can grow to over 40 feet long. But even the Giant Squid isnt as giant as its cracked up to be: this elongated invertebrate weighs only a few hundred pounds, and its cousin, the Giant Octopus, is only about the size of a well-fed fifth-grader. If these real-life cephalopods are nothing like the monsters depicted in movies and unscrupulous TV shows, imagine how much license producers take when it comes to the long-extinct Megalodon! Everyone clear on this? OK, time for some questions and answers. Q. Isnt it conceivable that a Great White Shark could be 30 or 40 feet long? After all, there are well-documented examples of 20-foot-long Great Whites, and 30 feet isnt that much bigger. A. Lets put it this way: the late NBA star Manute Bol was one of the tallest human beings who ever lived, at seven feet and seven inches. Does the fact of Manute Bols existence mean that human beings can potentially grow 10 or 11 feet tall? No, it doesnt, because there are genetic and physiological constraints on how large any given species, including Homo sapiens, can grow. The same logic applies to all animals: there are no 40-foot-long Great White Sharks for the same reason there are no five-foot-long house cats or 20-ton African elephants. Q. Megalodon swam the worlds oceans for millions of years. Why is it so impossible to believe that a small population, or even one individual, has survived into the present day? A. A species can only prosper as long as environmental conditions are conducive to its continued existence. In order for, say, a population of 100 Megalodons to thrive off the coast of South Africa, their territory would have to be stocked with the kinds of giant whales these sharks feasted on during the Pliocene epoch--and theres no evidence for the existence of these giant whales, much less for Megalodon itself. As for the persistence into modern times of one lone, ornery individual, thats a tired cultural trope directly traceable to the original Godzilla movie, way back in the 1950s--unless youre willing to believe that Megalodon has a million-year life span. Q. Ive seen reasonable-looking people on nature shows who insist theyve seen 40-foot-long sharks. Why should they go out of their way to lie? A. Well, why would your Uncle Stanley lie when he said that Bluefin Tuna ​that got away was seven feet long? Human beings like to impress other human beings, and they arent very good at estimating the sizes of things that lie outside a human scale. In the best cases, these people arent intentionally trying to deceive anyone; they just have a misplaced sense of proportion. In the worst cases, of course, they are intentionally trying to deceive the public, either because theyre sociopaths, theyre out to make a quick buck, or theyve been instructed to misrepresent the truth by TV producers. Q. The Loch Ness Monster surely exists. So why cant there be a living Megalodon off the South African coast? A. As Lois Griffin once said to Peter on Family Guy, Hold on to that thought, because Im gonna explain to you when we get home all the things that are wrong with that statement. There is absolutely no reliable evidence that the Loch Ness Monster (or Bigfoot, or Mokele-mbembe) actually exists, unless you want to credit the kind of fuzzy, forged photographs that shows like Megalodon: The Monster Shark Lives traffic in. In fact (and Ill probably be wildly misquoted here), Im inclined to say that theres LESS evidence for the existence of Megalodon than there is for the Loch Ness Monster! Q. How can the Discovery Channel lie about the existence of Megalodon, or giant Great White Sharks? Isnt it legally required to state the facts? A. Im not a lawyer, but based on all the available evidence, the answer is no. Like any TV channel, Discovery is in the business of making a profit--and if hogwash like Megalodon: The Monster Shark Lives or Megalodon: The New Evidence brings in big bucks (the former shows 2013 premiere was viewed by five million people), the networks executives will gladly look the other way. In any case, the First Amendment makes it nearly impossible to hold broadcasters like Discovery to account: they have a constitutional right to spew half-truths and lies, and the public has the responsibility to doubt all of the evidence presented on these shows.