Some very old oyster shells found in a cave have answered the eternal question, “who was the first person to eat that”?! Looks like it was a hungry South African, 164,000 years ago.

Today, we consume around 8 billion oysters a year. But they’re good for so much more than eating.

Oysters cement themselves together to form reefs that control coastal erosion and reduce wave energy.

These reefs increase the surface area 50 times compared to a flat ocean bottom, providing habitat for many other species.

Oysters filter water through their gills to extract and eat plankton—and in the process purify it, removing harmful chemicals and sequestering them in their shells. A single oyster can filter 50 gallons of water a day!

In the 1880s, Chesapeake Bay’s oysters could filter the entire bay in several days. Today, it would take more than a year.

That’s because oyster populations have declined there and worldwide. Some estimate Earth has lost 85 percent of its oyster reefs to overproduction, oxygen depletion and habitat destruction.

Thankfully, we’ve begun to appreciate their many benefits, and there are efforts underway to restore oyster beds. In New York Harbor alone, a project has grown 10 million oysters a year and aims to grow a billion by 2035.

They may not be much to look at but oysters are a vital part of Earth’s ecosystem.