Armed to the Teeth: Bites from Forgotten Sharks

As the 31-day stretch of August rapidly rushes to completion, and the balmiest days of summer fade into the imminent, cool veil of fall, 2014 also discards one of its temporal landmarks associated with these heat-stricken days. If you think I am referencing something remotely anapestic and evoking chest-fluttering nostalgia of long-forgotten, canicular childhood summers, then think again. Because I am, of course, talking about Shark Week.

Yes, that now-legendary bit of the Discovery Channel’s summer programming line-up, a selachimorph-centered festival that is closing in on three decades running, has now passed us by, ending but two weeks ago. Years ago, Shark Week initially appeared to be driven with the mission statement of Discovery in mind, one rooted in the dissemination of fundamentally educational, science-based material in an entertaining manner. This incarnation of Shark Week was the one I was fortunate enough to grow up with, and this week was a boon to my insatiably science-curious child brain, one that my neurons practically salivated over in Pavlovian form right around the time the last traces of abandoned, burnt out firecrackers left July’s dirt. The gift of science education excellence was instrumental in the development of my eventual fascination (and career trajectory) with biology, and I credit the old-school Discovery Channel’s programming with much of the inspiration and intrigue about the natural world that gilded my early days.

At the age of four, my shark ID skills were solid. However, my artistic skills were still…er….buffering.

So, given the intimate intellectual relationship I have with Shark Week and Discovery, watching what both entities have become in recent years feels like a steel-toed kick to the kidneys. There are a laundry list of offenses, and all of them hit on a single formula; the sacrifice of ethics and scientific accuracy in favor of mythology and adrenal-gland massaging codswallop; a grand invasion of heart-pumping, flash and sparkle nonsense programming based on approximately zero micrograms of actual science, all as an ill-conceived motion to inflate ratings. Some examples of Shark Week contrived falsehoods? Well, there’s this lovely bit of mass hysteria-inducing, publicity-hungry deceit initiated by cries of “oh no! Lake sharks! *wink wink*.” Also, there’s that time Discovery trotted out this steaming, embarrassingly unscientific pile of horseshit. Oh, there’s also that other time they made an entire special up. Or how about how the network can only seem to convince scientists to do Shark Week specials with them if they straight-up con them into doing so?

Others (linked above) have done a splendid job of calling out the network’s recent, fraudulent Shark Week habits, so this post isn’t going to be yet another dart in that already well-pockmarked board, but what I want to address is loosely tied to Shark Week’s newfound adoration of Megalodon (well, specifically an adoration of tricking viewers into believing the very extinct shark is still patrolling the deep…now for two years in a row).

“Megalodon”, or to be more accurate Carcharocles megalodon (or Carcharodon megalodon, it depends on what paleontologist you ask) is a popular beast, and thus is an obvious choice for many an examination by television networks (in mockumentaries or not). The extinct shark species is popular for damn good reason, too. C. megalodon was an animal of such outlandish proportions that it doesn’t seem like it could ever have existed, and yet it did, for more than 26 million years, dying out right around the time our ancestral line first harnessed that hot, orange, light-producing stuff that eats up wood (followed swiftly by the invention of S’mores and crappy ghost stories). This was a shark that, according to the most conservative estimates, exceeded 45 feet in length, and had a pair of cartilaginous bear trap-esque chompers big enough to gulp down a Ford Fiesta without even scratching the paint on its immense, triangular teeth.

And oh yes, those teeth. Those frisbee-sized blades that festooned its jaws in a ragged chain of despair. Those famous teeth, for which the animal is named (megalodon basically means “giant fucking tooth”), combined with a body bigger than a goddamn school bus, have enraptured the imaginations of young and old alike, and contemplation about what it would be like to encounter such a surreal, monstrous animal in the flesh is unavoidable.

But, here’s the deal with ol’ Megs…outside of its status as by far the largest shark that ever lived, and definitely one of the biggest predators to ever exist (getting edged out by the sperm whales alive today)…as far as we can tell, there’s nothing insanely unique about its biology. Granted, one of the most fascinating things about C. megalodon is that we don’t know that much about it. Even the size of the thing is sort of up in the air, seeing as how the scientific community has only fragmentary remains (teeth and a handful of vertebrae; the cartilaginous skeletons of sharks don’t fossilize as readily as bony skeletons, so this dearth of recorded remains is not that unusual) from which to base their calculations; estimations range from the 40s of feet in length to more than 60 feet…which in my book is the difference between “we’re going to need a bigger boat” huge and “I’m going to need a new pair of pants” huge.

Honestly, C. megalodon was cool and all, but it was basically just a Hulked-out version of any large lamniform shark (Lamniformes being the order of sharks to which great whites and makos belong). The animal is more or less like a great white had a run in with Rick Moranis and his growth ray, with maybe some very subtle differences in proportions…and a slightly different taste in prey…like taking on goddamned whales instead of comparatively diminutive sea lions. Yes, C. megalodon was something of a specialized whale killer…a shark exquisitely well-adapted to slaughtering and consuming the most massive animals of all time.

So sure, it’s teeth were heart-stoppingly big, and robust, and belonged in the titanic jaws of a beast of celebrity status….but they were just relatively standard lamniform teeth ratcheted up in size, with some limited modifications for slicing through several hundred cubic feet of whale flesh and bone at a time (increased thickness and bigger, deeper roots). For an animal so well-known for its mouth, it certainly didn’t have the most unique pearly whites among extinct sharks. The diversity of prehistoric sharks, and the diversity their feeding adaptations (which often are very divergent from today’s sharks), are woefully unappreciated, at least in comparison to C. megalodon, which is a remarkable shark due to its size and power…but I can think of a couple examples of long-extinct sharks that have far more interesting things going on at their eating ends.

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Evolutionary Anachronisms

The avocado.

You may think you have a good relationship with the avocado. The buttery fruit of this plant may regularly accompany your turkey sandwich, sliced and fanned out across the bread. Or, it may serve as a hearty dip in the form of guacamole. More recently, avocado is seemingly being utilized in a greater variety of ways, being deep-fried, thrown in macaroni and cheese, and finding its way onto burgers, Subway sandwiches, and even into ice cream. You’d expect that with all this attention, our green-fleshed, knobby-skinned friend, the avocado, would be content with its current role in human culinary efforts.

However, the avocado may very well be lonely.

Despite all our affection, this loneliness stems from the avocado potentially having eyes for another. I mean this, of course, in the sense of the concept of co-evolution (which I examined in a previous post), which is directly tied to the reproductive role of the fruit itself. The main function of a fruit (a botanical fruit, typically meaning the structure derived from the reproductive tissues of the flower housing the seed(s)), is to move seeds away from the parent plant and into areas that promote growth and survival. Many types of adaptations in fruits exist to help achieve this goal of seed dispersal; from the wind-catching dual blades of maple tree fruits (known as samara), to exploiting the appetites of the ubiquitous (and notably mobile) animals in the neighborhood. This latter evolutionary strategy involves the development of fruits that enrapture animal taste buds and provide irresistible caloric value, allowing consumed seeds to travel safely inside the gut of an unwitting, far-traveling chauffeur until being excreted away from the crippling shade of the parent plant. This is called “endozoochory.”

Most endozoochorous fruits have evolved to be eaten by fairly specific animals. Predictably, fruits adapted to be taken by songbirds are going to have different physical attributes than those associated with insects or elephants. You can try and fit a peach pit through the body of a sparrow, but you aren’t going to get very far. Similarly, expecting tiny, thin-walled seeds to withstand an elephant’s battery of grinding teeth isn’t realistic either. The suite of fruit traits evolved for dispersal by a given group of animals roughly categorize into “seed dispersal syndromes.” By interpreting these syndromes, we can often get a good idea of what the primary dispersing animal, the other partner in a co-evolved relationship, is likely to be.

In light of this, it becomes obvious that despite our love of the avocado (specifically, domesticated cultivars with lots of flesh; wild avocado fruits have a thinner layer of green deliciousness surrounding that pit), it is not “meant” for human consumption and seed dispersal. Any attempt to chew up the whole fruit and swallow the massive pit is bound to land your asphyxiating ass in the cemetery. However, the situation for avocado’s seed dispersal isn’t much better in its wild Neotropical range. Many smaller animals (like monkeys) that partake in avocado consumption are “pulp thieves”, ingesting the oily layer and tossing the seed at the base of the parent tree. In fact, no native animal is known to consistently and effectively disperse wild avocado. Why then does the avocado make a big, energetically expensive fruit that doesn’t cut the mustard on dispersal? Also, who is the true “buyer” of avocado’s product?

The answer to both those questions may be that the avocado’s chief dispersal agent is extinct. Kaput. Gone. Effectively an “ex-animal.” This would mean that the avocado fruit is an evolutionary anachronism, equipped with traits fine-tuned by evolution for interaction with a species that has quite suddenly disappeared, leaving the once perfectly capable seed vessel under-appreciated and inadequately used.

“Fruit’s almost ripe, guys. Come and get it! Hello? ….Guys?!”

It’s a very serious case of being all dressed up with nowhere to go.

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