Sharks are ubiquitous in our culture; from Jaws to Shark Week to Sharknado, we simply can’t get enough of these ancient and marvelous creatures. But almost as iconic as the animals themselves is an object they make every day and care nothing about: their teeth. Although shark teeth cannot be said to be rare, they nevertheless are considered by humans to be invaluable treasures.
Illustration of glossopetrae from A new and complete dictionary of arts and sciences, London, printed for W. Owen, 1763-6
Shark teeth have captivated us since ancient Rome, when Pliny the Elder discovered them embedded in rocks on land and assumed they had fallen to earth from the moon during an eclipse. In the Middle Ages, many believed these “glossopetrae” or tongues of stone to be the tongues of dragons and snakes, capable of warding off poison and other toxins, and would wear them as amulets. In ancient Hawaii, their uses were slightly more practical, where the islanders used them as utensils and weapons. But the truth of their existence and function are even more interesting than our ancestors predicted, if a little less fantastical.
Carcharocles megalodon, illustration
Sharks are members of a group of animals called polyphyodonts, which continuously grow new teeth throughout their lifespans. In combination with the extended lifespans of certain shark species (the Greenland shark is predicted to live up to 500 years), that adds up to a LOT of shark teeth; a single shark can leave behind up to 35,000 teeth in its lifetime! Shark teeth, like our own, are made of dentin, which is harder than the cartilage of their skeletons, but not regenerative like our bone-made skeletons. Because they are made of this hardier material, fossilized teeth are often the only remains of ancient sharks and are evidence for scientists and beach lovers to identify what types of sharks lived in the area.
One such beach lover is Steve Gladhill, a longtime beachcomber who has been collecting shark teeth fossils since he was a boy. His favorite place to find these treasures is the cliffs along the Chesapeake Bay in Calvert County, Maryland. Millions of years ago, these cliffs were underwater and hosted sharks of all types; as the water receded over time, their fossilized remains became exposed to the land, and have been deposited onto the beach ever since.
Steve’s shark tooth collection is so comprehensive (he says he has too many to count!) that he can tell which type of shark each tooth he finds came from and approximately how old it is. Steve’s advice to anyone interested in learning more about shark teeth is to join a local fossil club.
“These clubs take field trips to different areas to collect. I have met a lot of wonderful and knowledgeable people this way,” says Steve. “Plus, you gain access to beaches off limits to the general public.”
How big were megalodon? Megalodon (Carcharocles megalodon), whose name means “big tooth,” lived 23 to 3.6 million years ago, and was one of the most powerful predators that ever lived. They are thought to have averaged 34 feet (10.5 meters) in length, with some of the largest growing to almost 50 feet (18 meters) long. Above, left to right: Part of Steve Gladhill's fossil collection, Fossilized megalodon shark tooth compared to modern great white shark tooth, 1901 American Museum of Natural History leaflet comparing a man to a Megalodon jaw.
He and his partner Tammy Thatcher use some of the teeth they find to create necklaces as part of their business, STBeachFinds, where they sell sea glass and other beach finds in addition to shark teeth. Shark teeth aren’t the only fossils that marine animals leave behind. Steve also collects fossil teeth from other animals such as whales, fish, elephants, rhinos, and cave bears. His favorite finds include a stingray plate, a wahoo fish jawbone, and a cave bear tooth. He hopes to one day travel to the Badlands in North Dakota to hunt for dinosaur bones and teeth.
Shark teeth from living sharks also wash up on beaches as the animals lose their old set to make room for a new one. If you are a certified diver, you can look for teeth on the seabed. Sharks can be found in every ocean around the world, so wherever you go, there is a chance you will find a shark tooth.
Megalodon tooth found by Steve Gladhill.
Steve and Tammy’s appreciation of sharks and shark teeth is vitally important today, as many shark species are endangered due to commercial fishing and habitat degradation. As apex predators, sharks are incredibly important animals in marine ecosystems, keeping the balance of predator and prey so that no animal becomes too plentiful or too scarce. So the next time you come across a beautiful shark tooth on the beach, remember the beautiful animal that it came from, an amazing creature that will hopefully swim the ocean for millions of years to come.
Learn more about Steve and Tammy on Facebook @Stbeachfinds.
Learn how to identify shark tooth fossils ›
Shark fossils are not the only fossils from ancient seas found on beaches
This article appeared in the Beachcombing Magazine September/October 2019 issue.