*Article written by: Jayson Kowinsky - Fossilguy.com*

### The Size Of Megalodon

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

**Fast Fact:** Although this topic is much debated, and research continues, megalodon sharks did not get as large as many websites and documentaries say they were.
New research indicates a maximum body length of slightly over 50 feet as the limit in size for a megalodon shark. Some research argues
a maximum limit of around 60 feet for a megalodon. Regardles of either 50 feet or 60 feet, anything over 50 feet would be quite rare for a Megalodon.

*
Reconstructed megalodon skeleton at Calvert Marine Musuem. This is a reasonable size for an adult megalodon.
*

### Worlds Largest Megalodon Teeth

The tooth above is the worlds largest verified megalodon tooth. The tooth was measured by Paleontologist Craig Sundell and has a slant height of 7.48 inches. The tooth was found broken and glued back together. It was found in the desert of Ocucaje, Peru. This area contains the Pisco Formation which is famous for its large megalodon teeth. The tooth resides in a private collection. Images used with permission of paleontologist Craig Sundell. There are most likely other similar sized teeth found from this formation that have not been officially measured.

This is probably the worlds second largest megalodon tooth. It has a ~ 7 1/4" (184 mm) slant height.
This tooth was found by Vito Bertucci in South Carolina. It is in the collection of Gordon Hubbell.

### The Sizes of Carcharocles (Otodus) Megalodon

#### Introduction

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

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 are not made of bone, but instead are made
of soft cartilage which does not fossilize easily. We have no complete specimens of megalodon and only 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 of megalodon to living sharks of the same order, the lamniformes, such as the Great White and Mako sharks.

#### The Methods of Determining Megalodon Size:

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

#### The Many Studies:

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 have existed.

According to Dr. Mike Siversson, the largest tooth he measured came from a 19 m or **62 foot** 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.

However Shimada's new 2019 research (discussed below) suggests anything over **50.2 feet** is pushing it.

#### 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 (13 feet)

**- Juveniles** range from 4 to 10 m (33 feet)

**- Adults** range from 10 m and up (33 feet and up)

### The Very First Estimates of Megalodon Size:

The first ever attempt at a jaw reconstruction of megalodon took place in the early 1900's by Bashford Dean from the American
Museum of Natural History. In 1909 he reconstructed a jaw that exceeded 10 feet. Based on this reconstruction, the
resulting megalodon would have been over 80 feet in length. However, this reconstruction was based on unassociated sets of
South Carolina teeth, as no associated teeth had yet been found. Today, we have associated teeth and know megalodon was much smaller.

The image to the left shows Dean sitting in his reconstructed jaw. This image and his article is in the
The American Museum Journal: 1910, Volumes 9-10 page 232.

### The Recent Calculations of Megalodon Size:

There have been a number of proposed megalodon size calculations in the scientific literature. Below, I outline two methods and give charts for you to determine the size of your own megalodon based off your teeth.

### Shimada's Equations (Shimada, K. 2019):

This is the most recent method of calculating the maximum size of a megalodon.

Back in 2003, 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 had a different slope and intercept for each tooth position in the sharks jaw.
These equations gave maximum sizes around 59 feet for megalodon sharks.

However, in 2019, Shimada re-examined the crown height and total length of Great White sharks as well as the
rate of development of teeth as the shark ages. He again, used Great Whites, because they are the most similar
living lamniform sharks to megalodon, as they have broad and serrated teeth.

This time around, he found there was too much variation among upper lateral teeth, and all lower teeth to draw
definite conclusions. The only two teeth positions that gave reliable measurements were the first
two upper anterior teeth (A1 and A2).

Shimada analyzed these tooth positions, made a linear analysis like before, and
also made a new non-linear regression using the power function Y = aX^b.
The non-linear regression takes into account the size-related shift in teeth associated with the age of the shark (due
to dietary changes from juvenile to adult, and growth rate changes).

Shimada analyzed all of these regressions and concluded his older equations from 2003 overestimated the total length of the megalodon.

Shimada then combined the linear equation data from the A1 and A2 teeth to get a new maximum size estimate.
His linear equation for the average of the A1 and A2 postion is as follows:

Y = mX + b -> **TL = (11.788)(CH) + 2.143**
where TL is the total length of the shark in cm, and CH is the Crown Height of the tooth in mm.

Don't worry if you are confused or don't want to do the math, below is instructions and a chart how to find your megalodon size:

#### How to determine the size of a megalodon based on your tooth using Shimada's 2019 method:

**1. ** Determine the tooth position of your tooth. Unfortunately, Shamida says the lateral teeth and all of the lower teeth
are too variable to give an accurate size estimate. The equation only works for the upper A1 and A2 teeth.

Below is a figure from Pudry et al., 2001, showing an associated partial upper megalodon dentition and a composite lower dentition.
I have labeled A1 and A2 on the diagram. If your tooth is not an A1 or A2, you will have to 'guestimate' the size of the A1 or A2 based on your tooth position.

**2. ** Measure the **Crown Height** of the labial side of the tooth.
This is an important step. Do not measure the Slant Height, and make sure you use the labial side of the tooth.
Refer to sample image on the left showing what the Crown Height measurement is.

**3. ** Refer to the chart below to determine the megalodon length.
Again, this is only for the A1 or A2 postion. If you have another tooth position, you will have to make a 'guestimate' which will
introduce a ton of error.

**Notes:**

The largest upper anterior teeth Shimada measured with this method is specimen NSM PV-19896 and specimen FMNH PF 11306, both from
South Carolina. These are probably the largest curated megalodon teeth.

NSM PV-19896 has a taller Crown Height (12.0 cm) and gives a total length of 14.17 meters or 46.5 feet.
Shimada notes the largest megalodons based on museum collections would be somewhere between 14.2 and 15.3 meters (46.6 and 50.2 feet).

Read Shimada's full paper here **(Shimada, 2019)**.

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Size chart for Megalodon body size using crown heights of either Upper A1 or A2 megalodon teeth.
*

When using this chart, remember this is only accurate to A1 or A2 teeth. All the other positions are too variable.
Also rembember to use Crown Height, not Slant Height.

If the chart appears too small on your display device, click on it to see the full sized image.

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Partial Associated Megalodon Dentition from Purdy et al., 2001. Here, I label A1 and A2 tooth positions for reference.
*

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

This is an older method thats been handy for many years.
Gottfried based his measurements on tooth heights of Great 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 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.

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Chart showing Gottfrieds 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).

### 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.

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This a a 23 cm Megalodon Vertebra in Denmark - It's Figure 3 from: (Bendix-Almgree et al., 1983)
*

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, go
to the **Megalodon Shark Gallery**

## 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!

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 and extinction.

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

Apparel:
**
Megalodon T-Shirts from
Megalodon Mad Gifts 4 U.
**
If you're looking for something uniquely MEGALODON, these guys have a bunch of cool shirts! They come in a bunch of colors, styles, and sizes.
There are enough designs for even the most discerning megalodon fanatic!

**Get Your Very Own Megalodon Tooth:**

These are Authentic Megalodon teeth sold by
**
Fossil Era
**
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His Megalodon teeth come in all sizes and prices, from small and inexpensive to large muesum quality teeth.
Each tooth has a detailed descriptions and images that include its collecting location and formation. If you are looking for a megalodon
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### References / Works Cited

**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.

**Shimada, K**. (2019) *The size of the megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), revisited*. Historical Biology, DOI: 10.1080/08912963.2019.1666840