So, lately I’ve been thinking about teeth. Dentition is interesting. Choppers can be used to determine diet, infer foraging or hunting behavior, and indicate something about the biotic zones necessary for a species’ survival. All of which is interesting but not really important for our purposes today. Say hello to Mr. Shark.
This aged fellow has been cruising around Earth’s oceans since the Ordovician Period, some 400 million years ago. That’s a lot water under the bridge. Back then tetrapods hadn’t even burst out of the ocean yet, so it’s not surprising that sharks from this time period don’t leave lasting impressions. Even their teeth were dull.
For a good long time sharks just kept a low profile and swaggered around the ocean eating pretty much anything they could grab. Then about 100 million years ago, smack in the middle of the Cretaceous Period, the ancestors of today’s sharks bloomed into the teeth-gnashing monsters we know and love. Even the occasional dinosaur graced the lunch menu if they blundered deep enough in the water.
After a while, along came Megalodon, boasting seven-inch incisors. This guy would have made fearsome land dinosaurs hesitate to dip a toe in the big blue. Of course by then, the dinosaurs were gone and Megalodon and his buddies took advantage and became the world’s largest known shark, a true mega-predator. Tipping the scales between 50 and 100 tons, and reaching a length of seventy feet – Megs was a big old toothy beast.
Like other sharks, Megalodon shed teeth the way humans drop hairs and this helps us understand they once inhabited a global range until they disappeared during the Pleistocene about a million years ago. Minor fluctuations in habitat, climate, and food sources tip the balance for or against survival and after a run of more than 25 million years, Megalodon went extinct. Can’t say I’m sad about that, really. We’ve still got Megalodon’s descendents in the Great White shark and that’s toothy enough for me.
Prehistory is filled with amazing beasties – do you have a favorite? What do you think about Megalodon? Are you sad Megs no longer cruises the ocean, picking off a blue whale here or there? Just thinking how an occasional extinct species makes a sudden surprise reappearance gives a bonfire on the beach a higher safety rating than a week on a cruise ship.
Lesann Berry 
#1 by Traci Kenworth on April 12, 2012 - 7:37 am
Scary pictures.
#2 by Leslie on April 12, 2012 - 10:44 am
Aren’t they? I keep trying to get a handle on what a seventy-foot long shark would look like. That’s a good bit longer that my house. Everything is relative, eh? I thought Great White sharks were scary huge until I got a look at Megalodon.
#3 by jennifer tanner on April 12, 2012 - 4:20 pm
I wonder if Steven Spielberg knows about the Meg. It would make for a great follow up to Jaws. 🙂
#4 by Leslie on April 12, 2012 - 5:37 pm
Somebody had to have made a giant shark movie back in the 70s. Wasn’t that when all the big-bug and giant critter movies came out? I think I watched them all. Can you imagine the headlines? Jaws XXVIII – Megalodon Bites Back. They’d have to chase it down in a tanker or a cruiseship…Disney Cruise would provide more pathos. Just thinking out loud here.
#5 by Bridgette Booth on April 13, 2012 - 10:56 am
Okay, great. I haven’t been the same since Jaws, and now, you give me Meg to worry over. lol!
I always learn something when I visit you, Leslie. 🙂
#6 by Leslie on April 13, 2012 - 3:00 pm
I know the goal is to write stuff people connect with, but I just learn all this interesting stuff and want to share. I’m over the whole swimming in the ocean thing. Bathtubs are fine. Definitely a land animal here. Thanks for visiting!