An Oyster With Teeth Reveals When Mollusks Covered the Chesapeake Bay

Celebrate National Oyster Day by learning about the most bizarre oyster specimens in the National Museum of Natural History’s collection

What grows a calcium carbonate shell, breathes through gills and boasts an impressive set of humanlike teeth?

If you thought of a sea monster, guess again. It’s actually an oyster, and it has a story to tell about the history of the Chesapeake Bay.

In 1898, a dredging boat collected a set of dentures with an oyster attached to them from the bottom of the Chesapeake Bay. The strange specimen was sent to the Smithsonian Institution, where it has remained since — but not without pushback from several toothless individuals claiming ownership of the dredged-up dentures. One man insisted that the false teeth belonged to him, even though the dentures were found more than a decade before he was born.

Despite the specimen’s unusual appearance, this oyster was doing what all oysters do: searching for a safe hold above the mud. Once hatched, baby oysters swim freely through the water using tiny, hairlike structures called cilia. After a few weeks, they’re ready to settle down and develop a temporary foot that they use to crawl along the seabed in search of somewhere secure to attach themselves. While most oysters opt for a rock or another oyster, some have more unconventional tastes — and once they find a suitable surface, they don’t discriminate.

“If an oyster finds a hard substrate, it will frequently just grow on it,” said John Pfeiffer, research zoologist and curator of bivalves at the National Museum of Natural History. “Whether it’s a pipe, a pair of dentures, bedrock or another oyster.”

The young oysters produce an adhesive to cement themselves to their object of choice, where they’ll remain stuck for the rest of their lives. Oysters attached to smoking pipes and a teapot lid were similarly collected from the Chesapeake Bay around 1900 and are also housed in the museum’s collection.

“It’s like a little bivalve freak show,” Pfeiffer said of the ensemble.

These “freak show” oysters also provide a snapshot of the biological and cultural past of the Chesapeake Bay. Oysters were once extremely common there and provided the livelihood of Indigenous peoples, but today’s bay paints a bleaker picture.

European settlers overharvested oysters and dredged the bay, destroying large oyster colonies, or reefs. By the time the oyster attached to dentures was collected over a century ago, the oyster population was already falling. Today, due to overharvesting, disease, pollution and habitat loss, more than 99% of the historic native oyster population has disappeared from the bay. This decline has cascading environmental consequences.

As filter feeders, oysters remove contaminants from the water, improving the environment for other organisms. Conservationists are working to rebuild the Chesapeake Bay’s oyster reefs, but the oyster population is so diminished today that it takes nearly a year to filter the volume of the bay — a task the oysters could complete in just days back when the oyster-encrusted dentures were discovered.

The toothy oyster specimen is thus more than an eye-catching object of curiosity. It’s a remnant of a very different time for the Chesapeake Bay’s oysters.

“Oysters are an important part of our region's natural and cultural history,” Pfeiffer said. “These specimens are bizarre but they tell an ordinary story from the past — a time when oysters covered the Chesapeake Bay."

Ashley D'Souza | Read More

Ashley D’Souza is a science writing intern at the Smithsonian’s National Museum of Natural History, where they cover natural history research and collections news for the museum’s blog, Smithsonian Voices. Ashley is currently completing their master’s degree in science writing at MIT, where they write about any and all things wildlife. They also run the blog and YouTube channel, Confessions of a Bird Freak. In their free time, Ashley can be found wandering through the woods with their camera and binoculars and talking to trees and birds. See more of Ashley’s work at https://ashleydsouza.contently.com/ and https://confessionsofabirdfreak.com/.