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Ocean Portal by The Smithsonian Institution

Ancient Seas

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IMAGE GALLERY Shark Ancestors Long before great white sharks appeared, much larger ancestors roamed the ocean. This giant ancient shark -- the Giant Megatooth (Carcharodon megalodon) -- was probably big enough to eat a w...MORE GALLERIES


	PHOTO MORE PHOTOS Ammonite Like the modern nautilus, this relative of modern squid hunted from inside the s...
	TIMELINE MORE STORIES Top Predators Timeline What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is t...
	BLOG POST MORE STORIES New Archaeocetes from Peru Are the Oldest Fossil Whales from South America The evolution of whales represents one of the great stories in macroevolution. I...

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					Elevator Rudists May 1, 2013 - 9:48AMThese "elevator" rudists, an ancient bivalve, used one long heavy valve to anchor themselves in the sediment. They used their tentacles (shown here in pink) to filter food from the sea water. Discover more about the ancient...

Fossil Jellyfish

Apr 12, 2013 - 11:29AM

How long have jellyfish lived in the ocean? This jellyfish fossil is from...

Ancient Entoproct Community

Jan 18, 2013 - 10:28AM

For a long time, scientists thought that some small tentacled fossils were...

SPOTLIGHT


Did Whale Evolution Go Backwards? Whales swim, but their ancestors walked. Whales are mammals (like us) whose ancestors lived on land. Life probably began in...

Recliner Rudists Aug 9 2012 - 10:27am Where ocean currents were strong, ancient rudist “recliners” lay unattached on the seabed. Notice the pink tentacles, which were used to filter feed. Learn more about ocean life throughout deep time in our Ocean Over Time interactive or an image gallery.	Eocene Whales and Penguins Off the Coast of Peru Sep 12 2011 - 11:43am Offshore Peru, during the Eocene (~56-34 million years ago), showing three archaeocetes (ancient whales), along with a previously described fossil penguin.
Smithsonian Scientists Describe a 'New' Fossil Whale Mar 8 2012 - 11:22am Monodontids, the group of whales that includes the belugas and narwhals swimming our ocean today, are emblematic symbols of the Arctic. However, their fossil record, although scarce, suggests that these animals' ranges could have been much broader. Fossil monodontids have been previously found in...	Rudist Reefs Dec 4 2009 - 3:25pm About 100 million years ago, during the heyday of the dinosaurs, reefs were built by mollusks called rudist clams. They looked very different from today's coral reefs.
Ammonite Jan 26 2010 - 11:45am Like the modern nautilus, this relative of modern squid hunted from inside the safe haven of a protective shell. Ammonites went extinct around the same time as the dinosaurs—65 million years ago. Find more about ocean predators in our interactive timeline Who's on Top?	Fossil Jellyfish Apr 12 2013 - 11:29am How long have jellyfish lived in the ocean? This jellyfish fossil is from the Cambrian period, more than 500 million years ago. It was found buried in Utah—an area that used to be underwater, covered by the ocean. Fossil jellyfish are rare because they have no bones or other hard parts to turn into...
The Ocean Throughout Geologic Time, An Image Gallery Sep 20 2011 - 3:30pm Evidence shows that life probably began in the ocean at least 3.5 billion years ago. Photosynthesis began more than 2.5 billion years ago—the Great Oxidation Event. But it took hundreds of millions of years for enough oxygen to build up in the atmosphere and ocean to support complex life. The first...	Top Predators Timeline Sep 24 2010 - 6:00pm What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is the most fearsome hunter? It depends on where and when you look.
Submersible Collects Deep-Sea Corals Aug 12 2011 - 2:07pm Come along as scientist Dr. Brendan Roark narrates a submersible dive to collect and study deep-sea corals. Roark studies deep-sea corals to understand the history of the ocean and past ocean climates.	Rudist Clams Jan 26 2010 - 11:45am Rudist clams are mollusks that went extinct about 65 million years ago. They were the reef builders of the Cretaceous Period, the heyday of the dinosaurs. Today corals have taken over the role rudists once filled.
Cambrian Period (542 – 488 Million Years Ago) Sep 20 2011 - 4:20pm The basic body plans of all modern animals were set during the Cambrian Period, 542 - 488 million years ago. Your friends, family, and pet turtle may not look much like the creatures here. But we and our fellow animals are heirs of these ancient ocean dwellers. Changes in Earth’s climate and ocean...	Shark Ancestors Dec 17 2009 - 6:55pm Long before great white sharks appeared, much larger ancestors roamed the ocean. This giant ancient shark -- the Giant Megatooth (Carcharodon megalodon) -- was probably big enough to eat a whale.
Fossil Whale Found, Excavated, Jacketed, and Returned to STRI! Jun 23 2011 - 11:28am Jorge and I packed up the night we arrived in Panama with Aaron O'Dea and his team from STRI. The road we took in two field vehicles mostly followed the Panama Canal heading northwards; we had to stop at a tanker ship crossing, where the locks separated the roadway. Quite an engineering marvel.	Dugong Feeding Feb 3 2012 - 11:16am Dugongs, along with manatees, make up a group of marine mammals called sirenians or seacows. In the modern world, only one species of seacow is found in any one place in the world. However, the fossil record of seacows, which dates back 50 million years, tells a different story.
Ancient Entoproct Community Jan 18 2013 - 10:28am For a long time, scientists thought that some small tentacled fossils were early ancestors of jellyfish. But a new study has found that these ancient animals are actually related to an entirely different group of animals: the entoprocts, which are still alive today. The new fossil (Cotyledion...	Ancient Great White Shark Jan 26 2010 - 11:45am A scientific illustration of the most powerful fish of its time, Carcharodon megalodon, which swam the ocean 30 million years ago. This shark may have reached a size of 20 meters/66 feet. Meet other ancient top predators and modern great white sharks.