Something Big

sharkman6224 at my-deja.com sharkman6224 at my-deja.com
Tue Jan 18 05:22:50 EST 2000



>>jekel5 at email.msn.com [mailto:jekel5 at email.msn.com] wrote:
>>First, I want to apologize for jumping in on your conversation, but my
>>curiosity has gotten the best of me as well.

No problem, I'm glad my last posting stimulated your interest!


>>is it possible that this prehistoric giant would be capable of
>>surviving in today's oceans on larger fish such as the tuna.

Erm...I'd say it's unlikely (but not totally impossible).   It is true
to say that Mediterranean Sea has become home to the Great White Shark
(_Carcharodon carcharias_) despite the lack of pinnipeds (seals and sea
lions) by feeding on Dolphins and Tuna.   One could also argue that due
to the extensive problems associated with obtaining data from the ocean
depths that in todays technological climate there is no definite proof
that Megalodon doesn't still exist.   However, all data that we have
today about this shark indicated that it didn't prey principally on
fish, and considering its reputed size it is would need to consume vast
quantities in order to survive.

>>As well, what specifically do you mean by biologically rich
>>environments.

Those that have a high biodiversity.   Thus, they have a vast ammount of
fish, on which larger organisms feed, creating a complex food web.

>>What niche and environmental conditions do experts suggest would be
>>necessary for this shark to survive today?

It was known (from fossil evidence) to have fed on a now extinct species
of Baleen Whale, and thus similar conditions, with large prey (similar
in size and energy content to whales) and relatively warm temperatures.
  Even today, although the Great White feeds on Whale Carcasses it is
rare for it to hunt whales directly.

>>past 2 million years (when the species was expected to have died
>>off???), but is it even possible environmentally that this shark live
>>in current oceans.

It became extinct somewhere between 1 and 3 million years ago.   In my
opinion...no...   However, I should point out that I'm not an expert on
Paleoecology and others may be able to present a better arguement!

>>Has there been a reason suggested for the extinction of the Megalodon.

There are a number of hypotheses: Perhaps the competition of early
killer whales was too much; Maybe it fell victim to global cooling, or
shifts in whale populations to colder latitudes where the shark couldn't
follow.

>>And finally, where can I find information on the taxonomy of this
>>species. I understand that there is a long running debate as to where
>>this species fits, as a direct ancestor to the great white or more
>>removed.

Indeed, there is debate about whether it of _Carcharodon_, _Otodus_ or
_Carcharocles_ genera, which inturn relates to its ancestory to the
Great White!   Personally I go with the latter, and that _Isurus
hastalis_ ( a prehistoric Mako Shark) is the true ancestor of the Great
White.   There are a good reference for this:

Cresswel, J. Megalodon: Monster of the Oceans. Shark Focus iss.4 Apr.
1999: 12-13

There is also an entuire chapter devoted to it in:

Klimley, A.P. & Ainley, D. A. (Eds.)(1996). Great White Sharks; The
biology of C. carcharias. Academic Press, London.

also the below website is good, go to the Bill Heim on sharks section
and look for the Megalodon debate info.

www.elasmo.com

>>Thanks for the time, and thanks for providing such a great answer to
>>the previous inquiry!!

You're welcome.   I'm glad you enjoyed my last posting and that this one
is also of interest.   Let me know if I can be of further assistance .

                   Cheers,
                           -- M.B.


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