1. Megalodon: The Largest Shark that Ever Lived
Dana J. Ehret
Ph.D. Student University of Florida
Florida Museum of Natural History

2. Megalodon Exhibit Background
Will be open at the Florida Museum of Natural History from June 16th – Dec. 31st 2007.
Focal point of the exhibit is a 60-foot model of a Megalodon shark that visitors will be able to walk through.

3. Dr. Bruce MacFadden and Bob Purdy discussing the plans

4. If Shark Teeth Could Talk
Shark teeth can:
Identify the species
Lemon Shark
Mako Shark

5. If Shark Teeth Could Talk
Shark teeth can:
Sometimes indicate body size
Megalodon
Whale Shark

6. If Shark Teeth Could Talk
Shark teeth can:
Indicate prey or prey size
Great White Shark
Basking Shark

7. This Was One Big Shark!
Scientists still debate Carcharodon (or Carcharocles) megalodon’s size
Different analysis = Different size estimates
All studies conclude Meg was huge!
Most scientists feel Megalodon was between feet long

8. The Circle of Life
A shark’s skeleton is composed of cartilage, which does not preserve in the fossil record
However, shark vertebrae do calcify
Growth rings are preserved in shark vertebrae
Shark vertebrae are discs which are called centra
Growth rings are recorded in these centra
Number of rings indicates the shark’s age at death
Centrum with growth rings
Shark centrum
Tree rings

9. What did Megalodon Eat? Megalodon was the top predator of its time
It would need to eat a lot to survive
An adult female probably weighed over 100 tons
Megalodon most likely ate whales, large fish, seals, sea turtles, and whatever else it wanted!
Estimates show Megalodon would average 2,500 lbs of food per day!

10. When Was Megalodon Alive?
Megalodon lived from about 20 to 2 million years ago
Fossil teeth and (rarely) centra are found in ancient marine sediments
Megalodon is extinct!
Meg evolved to eat giant whales
that appeared as the oceans
cooled in the Miocene and
Pliocene

11. Where Did Megalodon Live?
Megalodon had a worldwide distribution
Cosmopolitan species
Adults lived offshore (pelagic)
Most likely had “nurseries” closer to shore
The Earth during the Miocene

12. Where do we find teeth today?
North America
Florida, North and South Carolina
South and Central America
Peru, Chile, Venezuela, Costa Rica
Africa
Morocco
Europe
Belgium

13. Collecting Megalodon
Shark teeth, including Megalodon, are the most plentiful fossils collected worldwide
They are abundant because sharks continuously grow new teeth and shed old ones, one shark can have 20,000 teeth in its lifetime
Megalodon teeth are coveted for their large size (up to 7 inches long)

14. All Different Sizes and Colors
Ascending Megalodon tooth sizes
Same shark different color fossil teeth

15. Shark tooth Identifications

16. Who is Megalodon related to?
Megalodon is a “lamnoid” shark related to modern makos, porbeagles, great whites, and many extinct species.
Scientists debate if Megalodon is directly related to the great white or if it was an evolutionary “dead-end”

17. Megalodon’s Ancestors

18. Megalodon’s Ancestors
Carcharocles
megaolodon
Carcharocles
auriculatus

19. Why did Megalodon become extinct?
Megalodon became extinct 2 million years ago.
Climate change during the Ice Age
Reduction in the number of large whales
Competition from other predators (sharks)
The Earth during the Pleistocene

20. Why is Megalodon Important?
Megalodon’s extinction carries a conservation message of relevance today
Understanding macroevolution of body size in sharks
Also understanding the extinction of top predators
Decline of modern shark species

21. Why is Megalodon Important?

22. MegaloMania
Megalodon has intrigued people for thousands of years

23. Misconceptions about Megalodon
Did Megalodon live at the same time as T-rex?
No. Non-feathered dinosaurs went extinct 65 mya. Megalodon evolved 20 mya.
Did Megalodon live at the same time as humans?
No. Megalodon went extinct 2 mya. Modern humans have only been around for 100,000 years

24. Misconceptions about modern sharks
Annual Animal Fatalities in the 1990’s
Deer – 130
Dogs – 18
Snakes – 15
Sharks – 0.4
Florida Tornadoes
188 tornado fatalities vs. 5 shark fatalities
Florida Bicycle Fatalities
1,520 bicycle fatalities vs. 4 shark fatalities
Sharks Are A Minor Threat!!

25. Questions?
© Jason Bourque , Florida Museum of Natural History