National Geographic

Like Shark Week, But With Actual Facts

It’s Shark Week, and the Discovery Channel have already jumped the shark with a fake documentary, asking if a giant prehistoric shark Megalodon is actually still alive. It’s not, and the show was filled with lies, fabrications and actors playing scientists.

Here’s a radical alternative idea: I thought I might celebrate Shark Week by telling you some actual facts about sharks. This, therefore, is a collection of my earlier Not Exactly Rocket Science posts on sharks (and a couple of rays, for good measure).

Cookie-cutter shark, by the NOAA Observer Project

Cookie-cutter shark, by the NOAA Observer Project

What Bit This Great White Shark? A Cookie-Cutter

On 25 August 2010, diver Gerardo del Villar, saw a great white shark off Guadalupe Island with two odd wounds on its head. One was a crescent-shaped scar. The other was a round crater, still open and bloody. Both were just behind the corner of the young male’s fearsome mouth. Del Villar took photos of the animal and sent them to a team of scientists, including Yannis Papastamatiou from the Florida Museum of Natural History.

He had seen wounds like these before. “A wound from a hook should leave more of a hole and would not be as smooth,” he says.  Instead, Papastamatiou thinks that they were the bite-marks of another shark, just a sixth of the size—a cookie-cutter. “I dont know of any other animal that leaves a bite like that.”

Thresher-shark

Thresher Sharks Hunt with Huge Weaponised Tails

For most sharks, the front end is the dangerous bit. Thresher sharks are the exception. They’re deadly at both ends, because they’ve managed to weaponise their tails. The top halves of their scythe-like tail fins are so huge that they can be as long as the rest of the shark. For around a century, people have been saying that the threshers lash out at their prey with these distended fins—hence the name. But no one had ever seen them do so in the wild.

In 2010, one team showed that they can lash out at tethered bait under controlled conditions. But Simon Oliver has done better. His team spent the summer of 2010 in the Philippines, watching and filming wild pelagic thresher sharks—the smallest of the three species—hunting large shoals of sardines. The videos are spectacular and unambiguous: threshers really do hunt with their tails.

Sand-tiger-shark

Credit: Jeff Kubina from Columbia, Maryland

Shark Dads Lose Babies to Unborn Cannibal Siblings

Inside its mother’s womb, an unborn sand tiger shark is busy devouring its brothers and sisters. It’s just 10 centimetres long but it already has well-developed eyes and a set of sharp teeth, which it turns against its smaller siblings. By the time the pregnant female gives birth, it only has two babies left—one from each of its two wombs. These survivors have already eaten all the others. They’re the bloody victors of a pre-birth battle.

Credit: Joshua Drew, Columbia University.

Credit: Joshua Drew, Columbia University.

Badass Shark Teeth Weapons Hint at Shadow Diversity

When life gives you lemons, make lemonade. When life sticks you on an isolated island surrounded by shark-infested waters, make utterly badass weapons out of shark teeth.

This is what the people of the Pacific Gilbert Islands have been doing for centuries. Sharks are a central part of their lives. Many social customs and taboos revolve around the finer points of shark-hunting. Young boys go through initiation rites where they kneel on a beach, looking towards a rising sun and slice their hairlines open with shark teeth, letting the blood run into their eyes until sunset. And with no metal around, they used shark teeth to adorn their weapons.

Credit: Diliff

Credit: Diliff

How the sawfish wields its saw… like a swordsman

If you ever saw a sawfish, you might wonder if someone had taped a chainsaw to the body of a shark. The seven species of sawfish are some of the wackier results of evolution. They all wield a distinctive saw or ‘rostrum’, lined with two rows of sharp, outward-pointing ‘teeth’. But what’s the saw for?

Barbara Wueringer has an answer: the saws are both trackers and weapons. They’re studded with small pores that allow the sawfish to sense the minute electrical fields produced by living things. Even in murky water, their prey cannot hide. Once the sawfish has found its target, it uses the ‘saw’ like a swordsman. It slashes at its victim with fast sideways swipes, either stunning it or impaling it upon the teeth.

Credit: Terry Goss

Credit: Terry Goss

Sharks gone walkabout – how Australian great whites ended up in the Mediterranean

In the 18th century, Europe started sending boatloads of white settlers to Australia. But unbeknownst to these colonists, Australia had sent its own white contingent to set up colonies in Europe, around 450,000 years earlier. These migrants were sharks – great white sharks.

When Chrysoula Gubili from the University of Aberdeen compared the DNA of white sharks from around the world, she found a big surprise. The great white is the most genetically diverse shark studied so far but the Mediterranean fish are only distantly related to nearby populations in the North-West Atlantic, or even in South Africa. Their closest kin actually live half a world away in the Indo-Pacific waters of Australia and New Zealand.

Credit: Barry Peters

Credit: Barry Peters

Widely set eyes give hammerhead sharks exceptional binocular vision

The hammerhead shark’s head is one of the strangest in the animal world. The flattened hammer, known as a ‘cephalofoil’, looks plain bizarre on the face of an otherwise streamlined fish, and its purpose is still the subject of debate. Is it an organic metal detector that allows the shark to sweep large swathes of ocean floor with its electricity-detecting ability? Is it a spoiler that provides the shark with extra lift as it swims? All of these theories hypotheses might be true , but Michelle McComb from Florida Atlantic University has confirmed at least one other -the hammer gives the shark excellent binocular vision.

Credit: Spotty11222

Credit: Spotty11222

Prehistoric great white shark had strongest bite in history

Thanks to Hollywood, the jaws of the great white shark may be the most famous in the animal kingdom. But despite its presence in film posters, the great white’s toothy mouth has received very little experimental attention. Now, Stephen Wroe from the University of New South Wales has put the great white’s skull through a digital crash-test, to work out just how powerful its bite was.

A medium-sized great white, 2.5m in length and weighing in at 240kg, could bite with a force of 0.3 tonnes. But the largest individuals can exert a massive 1.8 tonnes with their jaws, giving them one of the most powerful bites of any living animal.

Credit: Mark Conlin, SWFSC Large Pelagics Program

Credit: Mark Conlin, SWFSC Large Pelagics Program

Male and female mako sharks separated by invisible line in the sea

In the middle of the Pacific Ocean, Gonzalo Mucientes has discovered an invisible line in the sea that separates male mako sharks from females. The line runs from north to south with the Pitcairn Islands to its west and Easter Island to its east. On the western side, a fisherman that snags a mako will most probably have caught a male. Travel 10 degrees of longitude east and odds are they’d catch a female. This is a shark that takes segregation of the sexes to new heights.

Juvenile bamboo shark by Steve Childs

Juvenile bamboo shark by Steve Childs

Shark embryos use electric sense to avoid danger by freezing

Sharks can sense their prey’s minute electric fields, such as those produced when muscles twitch or nerve cells fire. This super-sense is part of what makes sharks such formidable hunters—you can’t hide from them if the very act of living can give you away.  But the tables are turned when sharks are young. As they begin life, they’re as vulnerable as any other fish, and their electric sense helps them to hide instead of hunt.

There are 17 Comments. Add Yours.

  1. Eric
    August 6, 2013

    Thank you so much for this! I have always been able to count on you guys! Shark week has been ruined.

  2. Mike
    August 6, 2013

    I’m disappointed in National Geographic for not understanding the purpose of a “mockumentary”. Your ignorance is just as sad as the rest of the masses who went into the program thinking megalodon was still alive. You all badly missed the point as well as some interesting aspects of the prehistoric shark’s life, behavior and end. This is why we can’t have nice things

  3. Maggie
    August 6, 2013

    Mike, I couldn’t have said it better! Lighten up people.

  4. Christopher
    August 6, 2013

    I agree. Discovery has long been a hole from which foul, putrid pseudo-science constantly spews. Shark week lost me years ago. Even as a kid I found their “science” lacking. It’s education “lite”, crap tv for the rubes who watch (and vote) for Sarah Palin and think it’s valid biology. Much like the lowest common denominator crap for the Animal Planet mermaid viewers who can’t tell reality from fiction.

  5. j
    August 6, 2013

    oh. our bad. I guess we got confused because “mockumentaries” are supposed to be funny. hence use of the word “mock.”

    yeah, natgeo, stop being so ignorant! (eyeroll)

  6. Marty
    August 6, 2013

    The point of a science channel is to not spread lies and hoaxes and pass it off as facts. YOU people seem to be the problem with today’s age in science based programs, YOU people do not seem to understand that these “Mockumentary” shows are making it harder for ACTUAL scientists to teach people the basics of evolution/natural selection and extinction. We are not overreacting, this is a valid and justifiable response to Discovery Channel’s ignorance, if anyone, Discovery should be blamed.

  7. Thomas R. Holtz, Jr.
    August 6, 2013

    What the naysayers in this thread are missing that the objection is NOT to the fact that it was a speculative mockumentary. The objection is that they did not market it as such, nor clearly state it. Even their “blink and you missed it” disclaimer did not claim that this was a fictional story.

    An actual documentary on the science of C. megalodon, which included reenactments of their life style and even a fantasy sequence of what it would be like if they were still there, would be perfectly fine. And fun. That isn’t what was provided.

    Instead, it was the pretense of a documentary which has actually convinced a sizable fraction of their audience that megalodon is indeed still alive: http://dsc.discovery.com/tv-shows/shark-week/polls/megalodon-poll.htm

  8. Adam King
    August 6, 2013

    Thank you for writing something meaningful about sharks. I have noted the decline in quality of Shark Week for several years, and now I refuse to watch it. It would seem that channels such as Discovery are now more focused on the entertainment value as opposed to providing meaningful fact. I dive with sharks almost weekly, and when I tell people this they are typically freaked out; but come with a plethora of questions. These are the types of inquiries that should be answered by something like Shark Week. The initial goal of the program was to educate people about sharks; an animal is this commonly misunderstood and also not widely represented or protected. Now it is more focused on “Air Jaws” and showcasing the apex species; Tigers, Bulls and of course Great Whites. Now that they can “up the thrill” with something like C. Megalodon, it is just another mechanism to get people to buy into the ferocity of the animals, not the actual science behind them. I was recently in the front row of a David Attenburough lecture and I unfortunately missed the chance to ask him a question. If I had, I wanted to ask his thoughts on the current state of documentary television and the value/repercussions it has on the natural world based on its content. Shark Week (as well as the vast amount of “Pawn Shop” and “Picker” shows) was foremost on my mind as an example of educational television that has been degraded based on mass appeal. It would have been interesting to hear his response, but alas I am without it. Here in Australia, there is a market for science interest and their version of Shark Week “Wild Sharks” hosts some of the best documentaries I have seen to date. One discussed the mating habits of Ragged Tooth (grey Nurse) off of South Africa and another titled “Strange Sharks” put the focus on some of the more derelict species like the Goblin and Cookie Cutter. This was all supplemented with older documentaries of the same quality such as “Alaska’s Killer Shark” based on Salmon Sharks and another where wildlife and fisheries was tracking Bull Sharks in local estuaries. But then i tuned back to Shark Week…..

  9. Adam King
    August 6, 2013

    @ Mike. I noticed your comment after posting mine and I wanted to clarify that the issue is not that people are so gullible to believe a “mockumentary”, but its that the genre has no place in “Shark Week”. As I stated above, the initial purpose of shark week was to educate people about sharks. Although pointing out the attributes of C. Megalodon are new fact to some people, it still does not dismiss the irrelevant points used as filler to base the rest of the show. Last year (or two years ago, i dont remember), Shark Week had the myth buster guys build a giant Megalodon model to show its size and also demonstrate its “bite strength”. After making said model, they used it to crush kegs and other material, which was not necessarily the best way to use their time. For the rest of Shark Week, the shows were focused on the same three types of sharks and trying to measure their bite, see them jump or instigate a scenario that causes the shark to show aggression; the opposite of what shark awareness truly strives to accomplish. This article is pointing out not only the banality of the programming, but its overall lack of diversity of information. Sure, there are some “facts” in these programs, but they are done in repetition year after year with no consideration to a species of animal that has over 440 different varieties (known) with a lineage dating back over 407 million years old (per the oldest known fossil). C. Meg was cool and being from Maryland where you can uncover teeth in the Calvert cliffs, it is even sentimental; but Helicoprion, and the Ancient Makos (from which Great Whites emerged; not C. Meg like Discovery has stated in years passed) are just as interesting. Bottom line is; If you are interested in sharks, then one would think that something called Shark Week would provide more interesting and relevant information, considering it comes from a channel that has adopted the moniker: Discovery.

  10. sitio
    August 6, 2013

    What – that wasn’t real!?!?

  11. Grace
    August 7, 2013

    I actually enjoyed those facts. Regardless whether or not they were because of a fake t.v show. thanks for that NatGeo.

  12. Mark Kawakami
    August 7, 2013

    I’ve been fascinated by sharks since I was in second grade. When I was 12, someone gave me a National Geographic documentary on sharks for Christmas. I probably watched that thing a hundred times. It was packed, from beginning to end with fact after fact about these amazing creatures.

    Naturally I’ve watched Shark Week every year, and even though there have been a few exceptional programs on Shark Week, I haven’t seen one that even comes close to that National Geographic documentary I watched so many times.

    The reason I’m bringing this up is to point out that it’s absurd to criticize National Geographic of all organizations of misrepresenting the informational value of a fake documentary when they’ve shown quite handily just how entertaining, informative and fascinating a real documentary, with real facts and real science and real scientists can be.

    And for the record: “Megalodon” wasn’t a mockumentary. Spinal Tap was a mockumentary. Best in Show was a mockumentary. “Megalodon” was just a bunch of lies.

  13. Eric
    August 7, 2013

    I am a fervent fan of Shark Week and look forward to watching it every year. This year is of no exception. I enjoyed the Megalodon opening episode and watched this with my wife and kids. I was bombarded with questions, as I like to think of myself as a shark enthusiast, from my family. Some of the questions were: “Is this show real?”, “Can a shark sink a boat?”, “Didn’t the Megalodon die out millions of years ago?”, etc. The first question I answered wholeheartedly with, “If it were real, you think I would have told you?” This wasn’t a “smart-ass” response, but a fair answer as I do read the news on a daily basis – and anything with ‘shark’ in it is fair game.
    I don’t think the purpose of the Megalodon episode was to mis-lead the viewing public (remember the Mermaid episodes – enjoyed them, also) but to make people more aware of what IS out there. If this single episode allowed my kids to ASK questions about which shark is capable of jumping out of the water, or swimming almost up on shore, I would consider this an excellent teaching experience.
    Discovery has, in recent years, pushed too much of the same episodes like “Air Jaws” and the infinite sequels, and biting force – too much is TOO much! There are 300+ sharks, only a handful are harmful to man, but we are harmful to all of them. I wish they could focus more on the odd sharks than delegating them to only a footnote in the Megalodon episode – Megamouth, Frill, etc.
    Bravo! Discovery. I hope more kids watch this episode and become more aware of what does and doesn’t exist in our backyard waters.

  14. Rdizzie
    August 7, 2013

    While I agree with the comments here about peddling these shows as fact in a “blare witch” fashion, we must realize that T.V. is first and foremost entertainment and little more. Peddling this mockumentary as real boosts ratings and ad space cost. Yes it is frustrating to those of us who actually care, for the average American this is no big deal and reality matters little to them. Though I think it has little to do with Sarah Palin, or any political figure as an above post stated, unless said political figure owns part of a t.v. station that partakes in such things. I watched this show and I thought, wow how cool this is that it is possible this shark still lives. However when the Shark after dark came on and those guys were laughing at the video of those people on the boat that died I knew something was amiss. Though they still said it was real footage in the live show. Also anyone who has ever fished knows catching big fish is not easy, and it is nearly impossible with the rigging used that a 50-100 ton animal would stay on the line for 2 hours as they video claimed.

    All this being said, yes mocumentaries can be fun, however they should be advertised as such. Our children are stupid enough, it irritates me to no end how children today take most everything they see on t.v. as indisputable fact. And they are determined to dismiss statements that t.v. is not reality even on reality shows. It is entertainment to sell ad space. This means extreme drama and impossible situations like the discussed Shark Week show.

  15. tab
    August 9, 2013

    I was disapponited with the opening show on the Megalondon. NO WAY IT CAN STILL EXIST. I have continued to watch all week. and he other shows have been good. I am an avid shark fan.

  16. Pongo the Urban
    August 20, 2013

    Some people think voting for Sarah Palin is valid biology?

    Well, I guess I can see it….

  17. Kathy S.
    October 17, 2013

    Thank you for making the correct, scientific methodological distinction between a theory and a hypothesis.

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