Waves cresting in the ocean.

Through Time

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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Featured Content

Photograph of the model of a Giant Megatooth Shark, taken from the front..

Shark Ancestors

A rendering of an underwater marine scene from the Cambrian Period, featuring an arthropod, annelids, and other animals.

A Collection of Cambrian Fossils

Two skulls belonging to extinct marine mammal herbivores used in the new study, both from the Smithsonian’s collections.

When Did Today’s Whales Get So Big?

A hippopotamus-like creature swims underwater

Flippers or Feet? An Extinct Mammal May Have Been Replaced By Today's Sea Cows

Although in reality an ichthyosaur and plesiosaur would have likely never battled, this widely shared lithograph by artist, geologist and paleontologist Henry De la Beche even inspired author Jules Verne to pen a similar scene in his book, Journey to the C

Unearthing History: Mary Anning's Hunt for Prehistoric Ocean Giants

Through Time Articles

This 1874 illustration of California gray whales (Eschrichtius robustus) shows a group of individuals at the edge of their modern day range in the North Pacific Ocean, blocked from traveling further east into Arctic waters by thick ice barriers.

In the Arctic, the Times, They Are a-Changin: You Can Pitch in to Understand How

Although in reality an ichthyosaur and plesiosaur would have likely never battled, this widely shared lithograph by artist, geologist and paleontologist Henry De la Beche even inspired author Jules Verne to pen a similar scene in his book, Journey to the C

Unearthing History: Mary Anning's Hunt for Prehistoric Ocean Giants

A hippopotamus-like creature swims underwater

Flippers or Feet? An Extinct Mammal May Have Been Replaced By Today's Sea Cows

The Komodo National Park site in Indonesia was inscribed on the World Heritage List in 1991. The site hosts "Komodo dragons" (Varanus komodoensis), a unique species that exists nowhere else in the world and is of great interest to scientists studying evolu

Tunicates—Not So Spineless Invertebrates

A shark tooth embedded in a bone

What the Megalodon Left Behind

Fossil mosasaur skull and partial skeleton sitting in what looks like the dirt it was excavated from.

If You Build An Ocean, Sea Monsters Will Come

the skull of a mosasaur

Meals of the Mighty Mosasaur

ichthyosaurs frolic in the waves

Form Equals Function for Ancient Sea Lizards and Modern Whales

A bright-green sea slug with a black background.

Sea Slugs: One Species at a Time

Mistaken Point New Foundland

Ediacaran Fossils: One Species at a Time

On average, Arctic sea ice has decreased by four percent per decade since the late 1970s.

Sea Level Rise

A Mesozoic Ocean scene

Ocean Through Time

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