Megalodon

[DavidPT40]

The Megalodon was supposed to be a 50 foot version of the Great White. So why did it go extinct?

I don't think it would have as many natural predators as the Great White. Certainly humans didnt cause its extinction.

 

[archman]

Here, maybe this will help.
http://www.elasmo-research.org/education/evolution/megalodon_extinction.htm

 

[deco_martini]

The Japanese ate em all.

 

[isurus]

The articles linked to on this page are quite interesting on the subject: http://www.megalodonteeth.com/about.html

 

[DavidPT40]

I'm thinking it has to be a lack of food that drove these giant sharks to extinction. I think habitat loss played a minimal role in reproductive failure. Whale sharks, along with a few other large sharks (mega-mouth, great white, greenland) still exist. A 12 foot long newborn megalodon wouldn't be very vulnerable. Killer whales might have been the only predator.

But, lets say that killer whales, great whites, and megalodons all fed on seals. The inter-species competition would be very great.

I doubt the megalodon would have been very successful against a healthy adult whale. Plus whales in pods have special defensive behaviors. So that would leave them to attacking sick whales and scavenging dead whales. A very infrequent meal at best.

 

[archman]

For something that only has fossil teeth remaining, I leave speculation for the experts. We don't even have a decent consensus on what the shark looked like. We know zilch about their reproductive biology. It could have been ovoviparous for all we know. Besides teeth, all we have to work with are the locations where we got the teeth.

A whole animal fossil imprint would be nice.

 

[sharky60]

I've seen them discribed as more of an 80' version of the bull shark, it supposedly had a very large head and upper body area more like the bull than the white.

I agree that is was probably a food source depletion as they went extinct around the same time the dinosaurs did or possible they may not have gone "extinct" at all, maybe they just evolved into a smaller shark like the white or bull.

 

[archman]

I've seen them discribed as more of an 80' version of the bull shark, it supposedly had a very large head and upper body area more like the bull than the white.

You didn't watch that awful scifi channel film did you? They also had a film on giant snakes, a giant dog, giant cat, giant worms... I think there was one on giant birds too, or maybe I'm getting carried away.


The best estimates put it ~50 feet. Sometimes one stills sees the greatly overexaggerated sizes reported, which are a hold back from the first attempt at a jaw reconstruction. That thing led to reports of up to 100' in the more optimistic circles.

As to head and body shape, that's up to educated speculation. Here's one of the more popular theories.
http://www.elasmo-research.org/education/evolution/megalodon_as_sandtiger.htm

Man, I love this website.

 

[novicediver]

That's the problem with shark fossils (or lack thereof) we have teeth and little else so we are stuck with extrapolations from what we know of modern sharks (which is still very little).

 

[dlwalke]

An important part of their diet, cetotheres (which was a small baleen whale) became extinct around the same time megaladon did and it has been speculated that this was a major contributing factor. Cetotheres was actually replaced by a different baleen whale, but unlike cetotheres, its successor was highly migratory and spent much of its time up in waters that were presumably too cold for megaladon to follow. Actually, I believe that when Megaladon prowled the seas, the seas were mostly warm throughout. In a more general sense, the cooling seas may have been a big factor, particularly if Megaladon, unlike the Great White, was not warm-blooded. If Great Whites were not warm-blooded, I believe they would not fare nearly so well insofar as much of their favored prey tend to hang in some pretty cool waters.