Illustration of an extinct tentacled sea creature.

Ancient Seas

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A Mesozoic Ocean scene

The Ocean Throughout Geologic Time

The ocean has gone through some dramatic transformations over time. This overview dives into our globe's ocean past.

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Color illustration of an ancient bivalve.

Rudist Reefs

An illustration of the megalodon shark.

The Megalodon

Forams are tiny single-celled organisms.

Foraminifera

A screenshot from video showing illustrations of ancient coral reefs.

Coral Reefs Changing Over Time

A Hawaiian petrel in flight

4,000 Years of Marine History through the Eyes of a Seabird

Are You An Educator?

At Smithsonian Ocean, we have lesson plans, activities, and resources to help you engage your students in the wonders of our oceans.

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Ancient Seas Articles

A rendering of an underwater marine scene depicting life ~145-65 million years ago, when rudist clams were the major reef builders.

Long Before Coral, Mollusks Built the Ocean's Reefs

Two men each hold a ceramic vessel at the archaeological excavation

Archaeologists Study Early Whaling Community in Quebec, Canada

A close-up image of a fossil shark jaw with teeth.

Shark Teeth Tell Great White Shark Evolution Story

Blue whale skull being installed at National Museum of Natural History.

When Did Today’s Whales Get So Big?

Smithsonian Scientists Dig a Trench Around a squalodontid Skull

Expedition to Excavate a Fossil Whale

Smithsonian researchers eat a meal in preparation for a fossil excavation

At STRI, No Whales Yet, But There Are Fossil Sea Cows...

Smithsonian scientists race the tide the excavate an ancient whale fossil entombed in rock

Fossil Whale Found, Excavated, Jacketed, and Returned to STRI!

Offshore Peru, during the Eocene (~56-34 million years ago), showing two archaeocetes (ancient whales): Ocucajea picklingi and Supayacetus muizon.

New Archaeocetes from Peru Are the Oldest Fossil Whales from South America

An illustration of multispecies communities of dugongs from India, Mexico and Florida

The Discovery of Multispecies Communities of Seacows

An illustration of a recently discovered species of Monodontid, Bohaskaia monodontoides, and its beluga and narwhale relatives

Smithsonian Scientists Describe a 'New' Fossil Whale

Nick Pyenson points to a skull and skeleton of a fossil whale.

Excavating a "toothed" baleen whale from Vancouver Island

A researcher holds an arm bone from a "toothed" mysticete whale from Vancouver Island.

Dispatches from the Field: Treacherous stream crossings and a new fossil find

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