EDEP Program Fall 2014 | Week 2: Megalodon’s Life
Lesson Topic
Where did Megalodon live?
When did Megalodon live?
What did Megalodon eat?
Lesson Objective
After this week students will be able to:
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Identify where in the world Megalodon lived
Recognize when Megalodon lived and what other animals he did or did not live with
Determine the diet of a creature given the shape of its teeth.
Words to know: cosmopolitan species, carnivorous, tooth morphology, cannibalism
Background Information
Where did Megalodon live?
Scientists do their best to estimate where Megalodon lived by looking at where fossils of the
enormous shark were found. Megalodon teeth have been found all over the world, indicating
that Megalodon was a cosmopolitan species. A cosmopolitan species is a species that lives all
over the globe. Megalodon was roaming the ancient oceans worldwide. Also, many Megalodon
fossils can be found on land, like on Florida’s coastal shores and in Peruvian deserts. Teeth
found on land and at higher elevations
indicate that these areas were underwater
during Megalodon’s reign. Because they
are no longer underwater, scientists
conclude that major climate change has
occurred over the past several million
years. Scientists also believe Megalodon
fossils are present in the world’s deeper
oceans, but they are difficult to find.
When did Megalodon live?
Megalodon roamed the world’s ancient oceans approximately 2-17 million years ago. This
includes much of the Miocene Epoch (5-25.5 million years ago) and almost all of the Pliocene
Epoch (1.8-5 million years ago). Megalodon did not live at the same time as humans, whose
first occurrence was approximately 100,000 years ago. Megalodon did not live at the same time
as non-avian dinosaurs (like Tyrannosaurus Rex), either. These dinosaurs went extinct
approximately 65 million years ago (around 50 million years before Megalodon). Because of
these facts, it is important to discourage notions from students that Megalodon lived at the
same time as humans or non-avian dinosaurs.
What did Megalodon eat?
Megalodon was a top predator while roaming the ancient oceans; the largest shark that ever
lived likely ate just about whatever it wanted! Scientists believe Megalodon fed on whales and
large fish to meet its food requirements. We know that Megalodon was carnivorous based on
the tooth morphology (the shape of the teeth) of the fossils. Megalodon had large serrated
teeth (the largest of any shark ever) that were capable of slicing large fish, whales, and other
sharks. Megalodon may have even partaken in cannibalism, consuming members of its own
species. Scientists infer these ideas from looking at modern sharks with smaller serrated teeth
and observing the kind of animals they eat. Based on Megalodon’s size, it is estimated that
Megalodon consumed an average of 2,500 pounds of food each day!
Activities
Where and When?
About 45 minutes
Objective
Students will use a map of the world and a rope to learn about where Megalodon lived and
when Megalodon lived, along with other facts about Megalodon’s life.
Materials
 Field journals
 World map
 Post-it notes
 100 foot measuring tape
 10 papers – labeled every 50 million years up to 500 million years
 Labels for students to hold that represents different activities along the timeline.
 Large, open space
Procedure
Part 1 – Where?
1. Begin this activity by asking students to guess where they think Megalodon lived. Allow
a good amount of students to guess without saying if they are correct. Once you have
sufficient participation, ask the students to think about how scientists would know
where the ancient shark was from. Lead the discussion to discovering that scientists
know where Megalodon might have lived based on where they found Megalodon fossils
(teeth).
2. Put up a large world map and have some post-it notes available. The students will then
come up to the board one at a time and put a post-it note in a place where they think
Megalodon may have lived; if they are wrong, you will take it down, but if they are right,
you will leave it on the map . Ask for volunteers.
3. Have volunteers come up and put a post-it note on the map one at a time. As each
student places it in a random spot in the world, act surprised that they guessed
correctly! Instruct the students to fill in their Field Journals to reflect the correct
answers. After each student puts it in a spot, also say, “Okay, so far we know Megalodon
lived in ________. Where else do you think?” and as more and more post-its go up all
over the map, keep on adding places to the list and start asking the students what they
think is going on. Lead them to realize Megalodon lived everywhere!
4. Introduce the term “cosmopolitan species” to the students and define it for them. Have
them record its definition in their field journals. Put another post-it note on land in
Florida and in South America and tell students that they even found Megalodon teeth in
these land areas. How is this possible? Lead the students to realize that when
Megalodon lived, there were areas that are land today that were completely under
water, suggesting enormous climate change. When exactly was this time period in which
Megalodon lived? This will transition into Part 2 of the Activity.
Part 2 – When?
5. When did Megalodon roam the ancient oceans? Tell students they are going to get to
take a guess based on a long timeline they are going to make. Start by bringing the
group to a large room or outdoors where there is open space. Unravel 100 feet of
measuring tape (either in a straight line or around a room) and explain that one end of
this rope represents 500 million years, the other end represents today, and everything
else is in between. Explain how this means that each foot represents 5 million years.
6. Discuss how 500 million years is a nice round number we are using. If we were going to
represent the origin of Earth using 1 foot=5 million years, we would need a rope that is
approximately ten times longer than this (4.6 billion years old). Mark along the rope
every 50 million years (using labeled paper) so the students can get an idea of where
certain events may go (it might even help to tape the sheets to it so that they will stay
put). Tell students you are going to read off some events in history and you need
volunteers to go up and represent these events on the timeline. Once we have all of
these events on the timeline, we can take guesses as to when Megalodon would fit in.
7. Read off this list (below) and put students in the correct spots (mya=million years ago).
Make sure you tell the students both where to go and how many years ago their spot
represents. The 50 million year markers should help guide this as well. Also, tell students
to remember what event they are representing.
 First sharks – 435 mya, 87 ft (from the side that’s present day).
 First land plants – 430 mya, 86 ft.
 First Insects – 385 mya, 77 ft.
 First reptiles – 330 mya, 66 ft.
 First mammals – 240 mya, 48 ft.
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First non-avian dinosaurs – 225 mya, 45 ft.
First birds – 220 mya, 44 ft.
First flowering plants – 115 mya, 23 ft.
Extinction of non-avian dinosaurs – 65 mya, 13 ft.
First modern humans – 100,000 years ago, 1/5th of an inch (feel free to take a
moment to discuss how short our time as humans on Earth has been relative to
other animals. Also, it will be interesting to bring up how the age of the Earth is
almost 10 times as long as this rope and humans have been alive for just 1/5th of
an inch’s worth of time.)
8. Now that all of these events are placed on the timeline (represented by students),
discuss when they think Megalodon lived. Did Megalodon live at the same time as
dinosaurs? Or humans? Allow students to guess where they think Megalodon fits into
the timeline. You can do this by letting them stand in front of the rope but a few feet off
of it, so their Megalodon guesses won’t get confused with the other events that are
already on the timeline and ask why they think so (was there land or water present?, did
other large animals live at the time? Etc.).
9. After students have guessed, give them the answers:
 First evidence of Megalodon – 17 mya, 4 ft.
 Extinction of Megalodon – 2 mya, 5 inches
10. Allow two students to represent these events on the timeline (check if any guessed
correctly). Discuss Megalodon’s time on Earth with the students. Make sure they realize
that Megalodon did not live during the time of the dinosaurs or humans. This is an
important misconception to overcome for students.
What Great Teeth You Have!
About 20 minutes
Objective: Students will identify different types of teeth that sharks may have, and infer a
shark’s diet given its teeth.
Materials
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Photo of a Basking Shark, Cookiecutter Shark, Basking Shark Teeth, Cookiecutter Shark Teeth,
Great White Shark Teeth, and Megalodon Tooth alongside GWS teeth (6 total)
Field Journals
1. Ask the students about what they think of when it comes to what sharks eat on a
regular basis. Do larger sharks eat larger fish? See if students agree, and have a discussion on it.
2. Show the students the picture of the Basking Shark. The Basking Shark is the second
largest fish in the world.
3. Next, show the students the picture of the Cookiecutter Shark, one of the smaller
species of shark.
4. Ask the students which species they think eats larger fish. The consensus should be
leaning towards the Basking Shark. Try to elicit examples of what each shark may eat, and see
who else agrees.
5. Tell the class that the Basking Shark only eats plankton, small fish, and tiny
invertebrates! On the other hand, Cookiecutter Sharks eat all kinds of fish, including large ones
such as tuna, dolphins, and even sharks. There have even been Basking Sharks that have bite
marks from Cookiecutter Sharks.
6. Ask the class if they still believe a shark’s size is related to its diet. If that is not the
case, then what can we look at in a shark to determine what it eats? If the students need a hint,
have them think about what teeth they use when they eat different things.
7. Looking at the shape of teeth (tooth morphology) is a great way to estimate what an
organism might eat. Have the students write it down in their field journals.
8. Show the students the picture of the Basking Shark’s teeth. The Basking Shark does
not need large, powerful teeth because they do not eat a lot of meat. They are filter feeders
that take in lots of water in their mouth and eat the tiny plankton in the water.
9. Go back to the first picture of the Basking Shark. Ask the students if anyone can even
see its teeth.
10. Now show the students the picture of the Cookiecutter Shark teeth. Note how sharp
the Cookiecutter Shark’s teeth are, and how curved the teeth of the upper jaw are. This helps
Cookiecutter Sharks take small bites even out of large fish.
11. Show the photo of a Great White Shark’s tooth.
12. Ask the students to look at the shape and size of the tooth to guess what a Great
White Shark would eat. Great Whites eat marine mammals (such as seals and dolphins) as well
as fish (even other sharks)!
13. Now, the students are going to figure out what Megalodon ate. Show them the
picture of the Megalodon tooth next to the Great White Shark teeth.
14. Given the tooth size and shape, as well as what they know about what the Great
White ate, have the students discuss what Megalodon may have eaten. If they said fish, sharks,
whales, marine mammals, they are all correct – and they used the same method as real
scientists to come to that conclusion! Have the students write this down in their notebooks.
Glossary:
Cannibalism: When an animal consumes members of its own species for food
Carnivorous: meat-eating; eating other animals for food
Cosmopolitan species: A species that lives all over the world
Tooth morphology: The shape of an animal’s teeth