Five surprising facts about sharks

Why are we so enamored with sharks? Why are we glued to the television in the summer during the last hours of daylight to watch fish on TV rather than playing a final game of wiffle ball or pick-up basketball? Does it have something to do with the fact that there are over 400 different types of sharks and always something new to learn? Anyway you slice it, these cartilaginous fish are pretty cool. Here are five surprising facts about sharks that will certainly get you excited to learn more and watch this year’s (hopefully) new and improved Shark Week. What is your favorite fact about sharks?

Shark Week will air from July 5-12 on the Discovery Channel

 

10 fish you don’t see during Shark Week

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.

Sink your teeth into this: 20 facts about shark teeth

Are you ready to sink your teeth into Shark Week 2012? Here are 20 facts about shark teeth to get you started. Discovery Channel’s annual event looks like it will quite the extravaganza  for its 25th year. Andy Samberg from Saturday Night Live has been brought in as the official ‘chief shark officer‘. I have my reservations about the summer ritual now as a marine conservationist (Read this article I resonated with last year “Should Shark Week Focus On Conservation?” from Care2.org), but love that it’s an event that brings people together and creates an interest in the marine ecosystem. I have many fond memories of my brothers, parents, and I slowing down at the end of summer to watch sharks in a way we never could from the shoreline.

1. Shark teeth are not attached to gums on a root like our teeth.
2. Sharks typically lose at least one tooth per week.
3. Sharks lose their teeth because they may become stuck in prey or broken and forced out.
4. Shark teeth are arranged in neat conveyor belt rows and can be replaced within a day of losing one.
5. Sharks average out to 15 rows of teeth in each jaw. Although most have 5 and then there is the bull shark that has 50 rows of teeth.
6. Shark teeth are popularly found as beach treasures because sharks shed 1000s of teeth in a lifetime. Although, don’t get yourself in trouble if you decide to collect them. Recently, over 2,400 shark teeth were confiscated from a passenger in India (shark teeth are an illegal import prohibited under the Wild Life Protection Act of 1972).
7. Well after a shark dies and its body decomposes its teeth will fossilize.
8. Fossilized shark teeth are not white because they are usually covered with sediment (which prevents oxygen and bacteria from getting to them).
9. It takes about 10,000 years for a shark tooth to fossilize. The most commonly found shark teeth fossils are from 65,000 year ago (the Cenozoic era).
10. Venice, FL (on the Gulf of Mexico) calls itself the “shark tooth capital of the world”.
11. Sharks are born with complete sets of teeth and swim away from their mother to fend for themselves.
12. A shark’s tooth shape is dependent upon its diet. For instance, the shortfin mako razor like teeth tear flesh, the tiger shark has piercing teeth to cut flesh, and the zebra shark has dense flattened teeth because it feasts upon mollusks.
13. Whale sharks have 3,000 little teeth that are of little use. They’re filter feeders that find food by sifting through their gills.
14. The tooth of the megalodon range from 31/2 – 7 inches long and can weigh more than a pound!
15. Shark teeth were recently discovered to contain fluoride.
16.  Sharks do not suffer from cavities.
17. The inside of shark and human teeth contains a soft mineral known as dentin.
18. The coating of shark teeth is acid resistant and less water soluble than our teeth.
19. Shark teeth and human teeth are equally as hard.
20. Even though many sharks have sharp teeth that could inflict a wound to humans, sharks should always be treated with respect.

Image (c) http://www.fancynancypantsinct.blogspot.com

What they’re into … with David Helvarg

This is a series I will be featuring each Tuesday this summer to get a special sneak peak at the different personalities behind the scientists, activists, and educators (including bloggers) who play an integral role in the marine science conservation field. It’s essentially an extension of the overwhelmingly popular and well done Tumblr blog, This Is What A Scientist Looks Like, (BCS was featured in April!) which sets out to illustrate that scientists are not just crazy haired nerds in lab coats. I’ve sent a list of 15 random questions to some folks I know and asked that each person share at least their answers to 5 of them. This first week we’re starting off with the one and only David Helvarg.

David is an author and Executive Director of Blue Frontier Campaign.  has written: Blue Frontier, The War Against the Greens, 50 Ways to Save the Ocean, Rescue Warriors and Saved by the Sea. His next book, ‘The Golden Shore – California’s Love Affair with the Sea’ will be out in early 2013. He is editor of the Ocean and Coastal Conservation Guide and organizer of ‘Peter Benchley Ocean Awards’ and ‘Blue Vision’ Summits for ocean activists. He has worked as a war correspondent in Northern Ireland and Central America, covered a range of issues from military science to the AIDS epidemic, and reported from every continent including Antarctica. An award-winning journalist, he produced more than 40 broadcast documentaries for PBS, The Discovery Channel, and others. His print work has appeared in publications including The New York Times, LA Times, Smithsonian, Sierra, and Parade. He’s done radio work for Marketplace, AP radio, and Pacifica. He has led workshops for journalists in Poland, Turkey, Tunisia, Slovakia and Washington DC. David is a licensed Private Investigator, body-surfer and scuba diver.

Here are David’s answers to his chosen questions:

What is the last thing you bought that you shouldn’t have?
A 12-pack of Coke.

What is your favorite Sunday breakfast?
Huevos Rancheros, fresh OJ and the Sunday New York Times, ideally on a porch with friends and a water view.

Are you a night owl or a morning person?
Can’t say I really give a hoot but neither do I wake up with a smile on my face.

What is your favorite room in your home?
My home office – just a 10 second commute from the bedroom.  If you work hard you get to play hard. 

What is your favorite scent?
The iodine and slightly kelpy odor of a living sea.

What is your favorite sundae topping?
Anchovies.  Only kidding.  Chopped nuts, chocolate syrup, whipped cream, it’s all good.

What is your favorite pastime?
Bodysurfing, diving, or snorkeling depending on conditions.

What three things would you take with you to an island?
Dive gear, my girlfriend and a boat.

How superstitious are you?
I believe in evolution and anthropogenic climate change so not very but I have given the occasional agnostic prayer for friends and loved ones in trouble.

What is your favorite day of the week?
Whatever day of the week I’m on a beach.

Are you a cat person, dog person, or neither?
Thought I was a dog person till I ended up in a 20-year relationship with a tabby named Poose, the finest small furry predator I’ve ever known or am likely to.

If you were a geometric shape, what would you like to be?
Elliptical.

Thanks to David for playing along and I hope you’re relaxing on the beach enjoying an ice cream sundae with plenty of chopped nuts, chocolate syrup, and whipped cream somewhere. To the dear rest of you, please keep an eye out for more to come from other amazing ocean conservationists this summer and please don’t forget to participate in the Summer Sustainability Creativity Challenge!