Wednesday, 4 November 2026

MEGALODON TEETH: WHAT ITS GIANT TEETH CAN TELL US

Megalodon teeth
A megalodon tooth is a wonderful thing to hold in your hand. The broad crown, thick root and finely serrated edges give us a sense of the animal behind it, even when the rest of that animal is missing. 

Some of the largest teeth approach 18 centimetres in length. That is a substantial piece of dental equipment, especially when we consider that whales were among the animals on the menu.

But size is only the beginning. Look closely at a tooth and we can begin to separate several stories: how it functioned in a living shark, where it sat in the mouth and what happened after it settled into the sediment.

ROOT, CROWN AND CUTTING EDGE

The pointed blade is the crown. Beneath it, the heavy root anchored the tooth in the mouth. Fine serrations run along the crown’s cutting edges, although these may be worn or missing in a fossil specimen.

On the inward-facing surface, near the junction of crown and root, a band called the bourlette provides another useful feature to examine. 

A broad triangular crown, fine serrations, a substantial root and this band help specialists recognise a typical megalodon tooth. Identification depends on the combination of features, along with comparisons and geological context. A large triangular tooth alone is not enough.

Shark teeth are made of dentine with a hard outer covering called enameloid. These mineralised tissues preserve much more readily than the cartilage forming most of a shark’s skeleton. We therefore have an abundance of teeth to study, while complete megalodon skeletons remain unknown.

A SHARK THAT KEPT REPLACING ITS TEETH

Sharks produce replacement teeth throughout their lives. As teeth are lost, others move forward to take their place. Megalodon shed thousands over a lifetime, leaving many opportunities for teeth to be buried and preserved.

This changes how we read a find. A loose fossil tooth does not necessarily mark the place where a shark died. Its owner may have lost it while feeding or during normal tooth replacement, then carried on swimming. The tooth began a rather different journey, into the sediment and eventually the fossil record.

SMALL POINTS, LONG HISTORY

The familiar megalodon blade developed within a lineage of megatooth sharks whose teeth changed through time. Some earlier forms carried small side points, called lateral cusplets, beside the main crown.

In a study of 359 fossil teeth from Maryland’s Calvert Cliffs, researchers traced a gradual decline in those cusplets through millions of years. The broad, serrated cutting tooth we associate with adult megalodon emerged through a lengthy transition.

Juvenile megalodon could also have cusplets, which complicates identification. Their presence does not automatically place a tooth in an earlier species. We need to consider variation within an animal’s life as well as changes across an evolutionary lineage.

The broad blade and serrations are consistent with cutting flesh. They help us understand how the teeth worked, but a loose tooth cannot identify its owner’s last meal. For that, we turn to other evidence, including bite marks on fossil bones and chemical clues preserved in tooth tissues.

WHY ARE FOSSIL SHARK TEETH DARK?

Fossil teeth often catch our attention because of their colour. Browns, greys and blacks reflect burial conditions and minerals in the surrounding sediment, rather than the colour of the living shark’s smile.

The root and crown can respond differently during fossilisation, so one tooth may preserve contrasting colours. Fossilisation does not require every part of the original tooth to be replaced by new minerals, either. Some of its original mineralised tissue can remain.

Colour belongs to the history of preservation. On its own, it cannot establish a precise age or confirm the species.

WHEN A SCHOOL LESSON CHALLENGED THE MEASUREMENTS

One of the most appealing megalodon research stories began with a classroom exercise. Palaeontologist Victor Perez and teacher Megan Higbee Hendrickson used replicas of teeth from one megalodon to help students calculate the shark’s length. Depending on which tooth they measured, the answers varied wildly.

The students’ arithmetic was not the problem. The exercise exposed limitations in the equations being used.

Teeth vary in size and shape around a shark’s mouth, so their original positions matter when we use them to estimate body length. Perez and colleagues went on to investigate a method based on tooth width. Their work offers a useful reminder that a fossil measurement and an estimate of a whole animal are different things. The estimate depends on a model, and that model needs testing.

A small tooth does not automatically mean a baby shark, either. It could come from a smaller individual, occupy a different position in the jaw or be missing part of its original structure. Context makes the measurement useful.

TAKE A CLOSER LOOK

Choose a clear tooth photograph, ideally showing both faces and a metric scale. Find the root and crown, then examine the edges. Are the serrations intact? Is the tip complete? Can we see the bourlette? What differs between the two faces?

Make a note of what is visible before deciding how it happened. A broken tip is an observation; an encounter with a particular prey animal is a proposed explanation that needs more evidence.

That distinction is useful well beyond shark teeth. It allows us to enjoy a fossil for what it preserves while recognising how much remains to be learned. With megalodon, one tooth can bring us close enough to study the cutting edge of an animal whose full outline is still a matter of research.

We will explore that missing outline in our next instalment, How Big Was Megalodon? Measuring a Shark We’ve Never Seen Whole.

Explore the growing collection in Megalodon: A Guide to the Giant Shark, or begin with Is Megalodon Still Alive? 10 Big Questions About the Biggest Shark.

FURTHER READING

Lead Image: Megalodon Teeth: Image Asset ID: 2099621176
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