Beach Chair Scientist

I confess. I’ve given up on Shark Week. It took 25 years to shake me, but for the first time I can remember, I won’t be watching. When I was 16, you couldn’t schedule enough great white and shark attack programming to satisfy me. Danger Beach, Vic Hislop, Air Jaws … it was all good. It’s obviously a winning formula for Discovery, but for me, it’s just not enough any more.

There are 500 species of sharks out there. Probably more. There are so many stories to tell. Here are ten you (probably) won’t see this year during Shark Week:

1. Ocean giants. The two largest fishes on Earth are sharks. Thirty-foot, plankton-eating basking sharks can filter a swimming pool of seawater every hour through sieve-like gill rakers in their throats. Whale sharks grow bigger than school buses, and gather by the hundreds in the waters off Mexico’s Isla Holbox and other global hotspots for seasonal feasts of zooplankton or fish eggs. Despite surviving on this surface-dwelling diet, researchers have also tracked whale sharks to depths of more than 6,000 feet. Why?

2. Glowing deepsea sharks. Lantern sharks glow in the dark and hide in the light. Many species of deepwater sharks, including the lantern sharks, are bioluminescent (i.e., they create their own light). Some of these sharks can even project light from their bellies that closely matches the light filtering down from above, erasing their silhouette. They also happen to be beautiful little creatures with fantastic names, like the velvet belly shark, the taillight shark, and the splendid lantern shark. Wouldn’t you like to meet a splendid lantern shark?

3. Cookie cutters. Shark geeks know all about the cookie-cutter shark, but I always forget that they’re not exactly famous…yet. A big cookie-cutter is less than two feet long and yet they’ve been known to feed on tuna, seals, dolphins, and whales…yes, whales. It’s a neat trick. The cookie-cutters sneak up on large prey, attach themselves with fat, sucking lips and twist and thrash until they pull free a round plug of flesh. These little sharks have a remarkable set of jaws with positively enormous teeth. In fact, the cookie-cutters have the largest tooth-to-body-length ratio of any shark (including the great white).

4. Wobbegongs. Can I interest you in a flat shark with patterns like bad 70’s wallpaper and a mustache that would put Tom Selleck to shame? Wobbegongs are bottom-dwelling masters of camouflage with ornate, branching lobes hanging from their upper jaws that look enough like algae or kelp to attract unsuspecting fishes and crustaceans. Wobbegongs lie in wait until their prey gets just a little too close, then erupt in an explosion of tassels and teeth.

5. Hammers and saws. You may have seen hammerheads during Shark Week, but have you ever seen a winghead shark? Wingheads have ‘hammers’ nearly half their total body length. To what benefit? Don’t know. What’s stranger than a hammerhead? How about a sawshark? Imagine a shark, with a chainsaw blade attached to its face and two long noodle-like nasal barbels for detecting buried prey. You can’t make this stuff up.

6. Here be goblins. All sharks have protrusible jaws. Their choppers are loosely attached to their skull, which allows them to push their jaws forward to get a little extra reach, or to create suction. Goblin shark jaws aren’t just extendable, they’re spring-loaded. Elastic ligaments are stretched taught when the shark’s mouth is closed and slingshot the jaws forward as they open. Goblins may need the extra reach to get out from under their long, wide rostrum…which looks a little like an ironing board (at least to me).

7. Helicoprion. You’ll hear plenty about the mega-monstrous megalodon this week, but I’d rather hear a little more about a real pre-historic elasmobranch enigma. Helicoprion had a strange spiral tooth whorl that early paleontologists had no idea what to do with. Some placed it in the sharks’ mouth, some on their dorsal fin. Some suggested it shot out like a frog’s tongue to ensnare their prey. Though speculation seemed to have settled on a lower jaw placement, at least one author suggests the teeth may have resided in Helicoprion’s throat.

8. The shark that walks like a dog. One of my favorites is the epaulette shark, a charming little carpet shark with a distinctive ocellated spot on its flank and a peculiar habit of locomotion. Epaulettes scamper across the reef on large pectoral and pelvic fins. Truthfully, these sharks look more like salamanders than dogs as they wriggle over complex coral reef habitats…and maybe a little like pigs as they root around in the substrate searching for food with their nasal barbels.

9. The sharks who’re named for cats. The catsharks are the largest family of sharks, and boast some of the strangest and most beautiful sharks in the sea. Some catsharks sport snappy colors and patterns like the striped pajama catshark and the chain dogfish (which is actually a catshark). Others are just bizarre, like the spatulasnout and lollipop catsharks, two hyper-specialized deepsea rarities. The aptly named swell shark gulps seawater (or air) and inflates like a pufferfish when threatened.

10. Sleepers. There’s not only diversity in size, shape, and appearance; there is also surprising variety in the ranges and habitats of sharks. Would you expect to find sharks beneath arctic ice sheets? Greenland sharks and Pacific sleepers are lumbering, flabby, but impressive beasts, surviving and thriving where you’d least expect. Stomach contents range widely from giant squid to halibut to seal and whale blubber to at least one (probably apocryphal) account of an entire reindeer.

That’s ten, but I’m still ignoring that other elusive plankton-feeding giant, the megamouth shark, not to mention the long-tailed threshers, the surrealistic rough sharks, frilled sharks, cowsharks, spotted zebra sharks, and puffadder shysharks. I won’t be watching, so if you hear more than a gee-whiz sound bite on any of these sharks, you’ll have to leave a comment to let me know and my faith will be restored.

I will credit Shark Week for creating a lot of excitement about sharks once a year. Some of the kids thrilled by the antics of bait-addled and target-tempted whites, tigers and other super predators will go on to become scientists, conservationists and marine educators…but many others will merely have tired shark stereotypes newly instilled or freshly reinforced. The challenge falls to educators, researchers, and shark enthusiasts to pick up the gauntlet and fill in the blanks for those viewers who just don’t know what they’re missing when it comes to the unappreciated (but critically important) diversity of sharks.

This post was contributed by Jim Wharton, Director of Conservation and Education at the Seattle Aquarium.