**
This Thursday evening (Sept. 29) from 7-8 pm (eastern) is the FOSSIL Project's 2nd Fall Webinar!
**

Bruce MacFadden is doing the next one on "Field Notes 101"

Go to
FOSSIL Webinar Series Forum
for directions on logging in to participate in the free webinar!

## The Size of Megalodons

How large was the megalodon that your fossil tooth came from?

**Fast Fact:** Megalodons did not get as large as many websites and documentaries say they were.
A maximum body length of
around 60 feet is now generally accepted. Anything over 65 feet would be huge for a Megalodon. Sorry, there is no such thing as a 100 foot Megalodon.

### How large did megalodon sharks get?

Obviously, we know they had MASSIVE teeth, with the largest having an over 7" slant height. But what does this tell us about
the size of the shark? How big did they get?

Well... we don't exactly know. This has been debated for some time and numerous methods of calculating the length of a megalodon
have been proposed. The crux of the problem is that sharks, like the megalodon, were not made of bone, but instead are made
of soft cartilage which does not fossilize easily. We have no complete specimens of megalodon and few partial specimens
(such as associated teeth and vertebra). Because of this, paleontologists cannot directly measure the size of a megalodon.
However, they can compare the preserved parts to living sharks, such as the Great White and Mako sharks.

This is one of the largest megalodon teeth.

It has a 7 1/4" (184 mm) slant height.

This tooth was found by Vito Bertucci in South Carolina.

It's in the collection of Gordon Hubbell.

**The Sizes of Megalodons**

Based on the measurement methods discussed below, scientists have a pretty reasonable estimate on the size of megalodons.

**The Largest:**

Pimiento and Balk did a study on the body-size trends of megalodon.
They reached a statistical maximum size of 17.9 meters, or **58.7 feet** (Pimiento & Balk 2015).
It's important to note this is a statistical maximum size, so ones over 18 m could exist.

According to Dr. Mike Siversson, the largest tooth he measured came from a 19 m or **62 feet** megalodon (Siversson, 2012).

Finally, according to Gottfried et al. in the 1996 paper, he uses data from a HUGE Great White from Malta and
uses the Great White / megalodon tooth ratio and comes up with 20.2 m, or **66 feet** for the maximum size of a megalodon.

So, it appears the largest megalodons, were probably over 60 feet in length, perhaps closer to the 65 foot mark.

**Average Sizes:**

Pimiento and Balk also found the average (mean) size of megalodons. They were around 10 m or **33 feet** in length
(Pimiento and Balk, 2015).

Gottfried et al., 1996 lists the sizes of megaldons in different life stages from Newborns (Neonates), Juveniles, to Adults.
In Pimiento and Balk (2015), they reiterate the sizes, and give the following information:

**- Neonates** reach sizes up to 4 m

**- Juveniles** range from 4 to 10 m

**- Adults** range from 10 m and up

This is possibly one of the worlds largest megalodon teeth. Based on the image, the tooth has a slant height of
slightly over 8". Based on Shimada's Method, the shark this tooth came from was between 60 and 65 feet!

It's in a private collection from Chile. Images used with permission of paleontologist Craig Sundell.

**The First (Now Invalid) Estimates of Megalodon Size:**

The first attempt at a jaw reconstruction of megalodon took place in the early 1900's by Bashford Dean from the American
Museum of Natural History. The reconstructed jaw exceeded 10 feet. Based on this jaw reconstruction, it was believed
megalodon could get over 100 feet in length. However, these reconstructions were based on unassociated sets of
teeth, as no associated teeth had yet been found. Today, we have associated teeth and know megalodon were much smaller.

More recent research, based on associated partial dentitions, show that a megalodon with 5 - 6" teeth would have had jaws
roughly around 6.5 feet wide and 8 feet high. One of these unassociated reconstructed dentitions can be seen at the
Calvert Marine Museum. The reconstruction is shown toward the top of this article.

#### The Recent Calculations of Megalodon Size:

There have been a number of proposed megalodon size calculations in the scientific literature. Below, I outline 2 methods, and give a brief description of a couple more complicated methods.

**Shimada's Equations (Shimada, K. 2003):**

How to correctly measure the crown

height of a megalodon tooth. This is the

Vertical distance, not the slant distance.

This tooth has a crown height of 7 cm,

and therefore would have come from

a 12.4 m (40 foot) megalodon.

This is an easy method that is used by many paleontologists.

Shimada studied the dentition of Great White sharks of known body size, He concluded the roots and the crowns
of the teeth did not grow at the same rate as the shark grew. Based on this finding, he came up with a
linear relationship (**Y = mX + b**) between the crown height of a tooth and the size of the shark.
He then used this equation to extrapolate the tooth size (CH) vs total body size (TL) of megalodon sharks.

This linear equation has a different slope and intercept for each tooth position in the sharks jaw.

Examples:

For an upper A2 tooth, the equation is **TL = 12.103(CH) + -2.16**

For a lower a2 tooth, the equation is **TL = 13.597(CH) + -7.643**

**How to determine the size of a megalodon based on your tooth using this method.**

**1. ** First, you need determine the tooth position of your tooth.

Below the charts are two figures from Pudry et al., 2001, showing an associated partial upper megalodon dentition and a composite lower dentition. I have labeled on the diagrams, the upper anterior 2 and lateral 4 tooth (A2 and L4), and the lower anterior 2 and lateral 4 tooth (a2 and l4).

**2. ** Second, you need to measure the **crown height** of the labial side of the tooth.
This is important step. Do not measure the Slant Height, and make sure you use the labial side of the tooth.
Refer to the diagram.

**3. ** Simply refer to the charts below to determine the megalodon length. I can't make charts for all 18 tooth positions. I have charts for the upper A2 and L4 position, and the lower a2 and l4 position. Measurements are both in English and Metric.

**Notes:**

This method is preffered by many paleontologists because it is relatively easy to use. However, this
method is based off of Great White sharks. Megalodons were more robust animals than Great Whites;
their teeth were made for crunching bone. Also, teeth size and shape not only vary from
position in the jaw, but also between individuals. As a result, the calculations may not be completely accurate;
the lengths may slightly underestimate or overestimate the actual megalodon length.

The largest teeth measured with this method are from the Gatun Formation in Panama (Pimiento et al., 2010) and (Pimiento et al., 2013).
Pimiento has a lower lateral tooth with a crown height of 2.81 cm (specimen UF 257579),
which gives a total length of 16.8 meters (55.1 feet) for the megalodon. She also has a specimen (UF 257579) that has a total
length of 17.9 m (59 feet)!

When using these charts, remember to look up the correct tooth position, and measure your tooth via the Crown Height.

If you use the wrong tooth position, the numbers are WAY off.

If the charts appear too small on your display device, click on them to see the full sized image.

Partial Associated Megalodon Dentition from Purdy et al., 2001. Here, I label the A2, a2, L2, and l2 tooth positions for reference.

Remember, when using these charts, the tooth sizes are based on the Crown Height of the labial side of the tooth. Refer to the paragraph above the diagrams to properly measure your tooth.

**The Older Method: Gottfried's Equations (Gottfried, et al., 1996):**

This is an older method thats been around for a while. It's been used on this website for some years now.
Gottfried based his measurements on tooth heights of Greate White shark teeth with known body lengths.
Although it was an invaluable method many years ago, many paleontologists do not use this method anymore
and instead use Shimada's method or other methods. Compared to other methods, Gottfried's equation
appears to underestimate the current consensus on the length of a megalodon.

His equation from his paper (Gottfried et al., 1996) is as follows: **TL(m) = a + b[UA2H(mm)]**

His equation (converted into cm) with the constants added in is:

**Length in meters = [(.96 x Upper A2 height in cm) - .22]**

To use this equation, you need an upper A2 tooth. Also, when taking measurements,
you need to measure the **VERTICAL HEIGHT**, not the labial Crown Height, or the Slant Height.

To use this method, take a vertictal measurement of an upper anterior 2 tooth from the root lobe to the tip of the crown and then
simply refer to the chart below. See the diagram showing how to measure it. The problem is, if you don't have an A2 tooth

One slight problem is if you don't have an upper A2 tooth, you need to "guestimate" the size of it based off your tooth and its
position. You may want to refer to the dentition image in Shimada's section for this.

Chart showing an older method of using A II tooth height to determine corresponding megalodon lengths.

##### Other Methods of determining the Length of a Megalodon Shark

There are other methods developed by other paleontologists. Some appear to be more accurate than Shimada's method, however they are more complicated and often require more than an isolated tooth.

**Jaw Perimeter:**

One method by Dr. Mike Siversson measures the total width of the teeth in the upper jaw and compares it to living sharks. (Siversson, 2012).
This method would be more accurate than basing measurements off of a single tooth because it uses more of the animal.
Siversson estimates the maximum size megalodon to be around 19 m or 62 feet (Siversson, 2012).

23 cm Megalodon Vertebra in Denmark

Figure 3 from: (Bendix-Almgree et al., 1983)

**Megalodon Vertebra Size:**

One of the most accurate methods for the megalodon size does not use teeth. Instead it used vertebra and compares
those vertebra to the lengths of similar sharks. Two researchers arrived at two different, yet similar, formulas
for estimating the size of megalodons by this method.

The first is from the 1996 Gottfried et al. publication. In this paper, they compared the body length and vertebra
size of the Great White shark and extrapolated it to megalodons. The equation is as follows:

**TL = 0.22 + 0.058(CD)**

Where TL is the total length of the shark in meters, and CD is the diameter of the largest vertebra centurm in mm.

The second vertebra method comes from Shimada (Shimada K, 2008). In 2008 he estimated the body length of
Cretoxyrhina mantelli, a cretaceous shark. His equation (converted to meters) is as follows:

**TL = 0.281 + .05746(CD)**

Notice both equations are VERY similar. The only problem with this method is examples of vertebra from megaldodon
sharks are rare. Also, you need the largest vertebra from the shark, which again is something very difficult to find.

A notable discovery of associated megalodon vertebra came from Denmark in 1983. A partial vertebra column
of a megalodon was excavated from the Gram clay. There were 20 associated vertebra, with the largest having
a diameter of approximately 23 cm (Bendix-Almgree et al., 1983).

Based on an average of both formulas above, this megalodon would have been around 13.5 m (44.3 feet) in length.

**I would like to thank Sam Cro for his expert help and input on this article. Thank you!**

For much more information about megalodon sharks, please go
to the Megalodon Shark Gallery

**Get Your Very Own Megalodon Tooth:**

These are Authentic Megalodon teeth sold by Fossil Era , a very reputable fossil dealer (that I personally know) who turned his fossil passion into a business. These Megalodon teeth come in all sizes and prices, from small and inexpensive 2 and 3" teeth to muesum quality 6+" teeth. Each tooth has a detailed descriptions and images that include its collecting location and formation. If you are looking for a megalodon tooth, browse through these selections!

**Recommended Books and Video about the Megalodon Shark:**

The following book: Megalodon: Hunting the Hunter is an impressive book about megalodons. This informative book is easy to understand, filled with interesting facts and has many high quality images. It's a must for any "Meg" fan!

MEG: A Novel of Deep Terror

A **FICTIONAL NOVEL** by Steve Alten, first published in 1997.

This is not a REAL science book about megalodons. This is a **FICTIONAL NOVEL** about a megalodon shark terrorizing
the California coast and the adventures of the main character Jonas Taylor.
"Meg: A Novel fo Deep Terror" and its sequals are fast and entertaining reads. The reason why I have it listed here is the movie
based on this novel is set to be released in 2017. Kind of like Jurrassic Park, I like to read the fictional novel first,
and then see the movie!

The National Geographic DVD:
Prehistoric Predators: Monster Shark
is the only Video I've found that actually has **real facts** about the Megalodon. It is not one of those garabage "mocumentaries" of recent.
National Geographic does a great job at presenting everything about the Megalodon, including it's paleoecology, extinction, and relationship to the Great White.

If you are looking for a real megalodon documentary, this is it.

**References:**

**Bendix-Almgreen, Svend Erik**. (15 November 1983) *Carcharodon megalodon from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoi'n*. Bulletin of the Geological Society of Denmark (Copenhagen: Geologisk Museum) 32: 1-32. (PDF).

**Gottfried, Michael D., Compagno, Leonard J. V., and Bowman, S. Curtis**. (1996) Chapter 7. *Size and skeletal anatomy of the Giant Megatooth shark Carcharodon megalodon*. pp. 55-66. IN: Klimley, A. Peter, and Ainley, David G. (editors). In: Great White Sharks the Biology of Carcharodon carcharias Academic Press. San Diego, CA. 517 pp.

**Pimiento, Catalina and Balk, Meghan A.**. (2015) *Body-size trends of the extinct giant shark Carcharocles megalodon: a deep-time perspective on marine apex predators*. Paleobiology, 41, pp 479-490. doi:10.1017/pab.2015.16.

**Pimiento, Catalina, Ehret, Dana J., MacFadden, Bruce,J., Gordon Hubbell**. (2010) *Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama* PLoS One. 2010; 5(5): e10552. Published online 2010 May 10. doi: 10.1371/journal.pone.0010552

**Pimiento, Catalina, Gerardo Gonzalez-Barba, Dana J. Ehret, Austin J. W. Hendy, Bruce J. MacFadden, Carlos Jaramillo** (2013). "*Sharks and Rays (Chondrichthyes, Elasmobranchii) from the Late Miocene Gatun Formation of Panama*". Journal of Paleontology 87 (5): 755-774. doi:10.1666/12-117.

**Purdy, R., Schneider, V., Appelgate, S., McLellan, J., Meyer, R. & Slaughter, R.** (2001). The Neogene Sharks, Rays, and Bony Fishes from Lee Creek Mine, Aurora, North Carolina. In: Geology and Paleontology of the Lee Creek Mine, North Carolina, III. C. E. Ray & D. J. Bohaska eds. *Smithsonian Contributions to Paleobiology, No 90.* Smithsonian Institution Press, Washington D.C. pp. 71-202.

**Siversson, Mike.** *"Lamniform sharks: 110 million years of ocean supremacy"* Royal Trell Museum Speaker Series. Western Australian Museum, Perth, Australia. March 28, 2012.

**Shimada, K**. (2008) *Ontogenetic parameters and life history strategies of the Cretaceous lamniform shark, Cretoxyrhina mantelli, based on the vertebral growth increments*. Journal of Vertebrate Paleontology 28: 21-33. doi: 10.1671/0272-4634(2008)28[21:opalhs]2.0.co;2

**Shimada, K**. (2003) *The relationship between the tooth size and total body length in the white shark, Carcharodon carcharias (Lamniformes: Lamnidae)*. Journal of Fossil Research 35:28-33.

Picture of some megalodon fossil shark teeth found over the years. Based on the above chart, the megalodon sharks these teeth come from would have ranged in size from 15 feet to 50 feet.