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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...
Like the modern nautilus, this relative of modern squid hunted from inside the...
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What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is the...

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These "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. And many often grew together to form...
Today, filter feeders like clams, sponges, krill, baleen whales, fishes, and...

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Whales swim, but their ancestors walked. Whales are mammals (like us) whose ancestors lived on land. Life probably began in...

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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...
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.
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...
When you're standing in a museum surrounded by fossils, you can almost imagine drifting through time to when long-extinct creatures swam the ocean. Found all over the world, these fossils can be read...
This illustration shows the edge of a warm inland sea during the Cretaceous Period, heyday of the dinosaurs. Constantly shifting sediment supported new groups of organisms, including rudist clams—...
Reaching almost three feet (one meter) long, Anomalocaris canadensis was enormous for this time period.
The peaceful Archaeocyatha lived during the most recent part of the Cambrian period. They separated into many families and were the Earth’s first reef-building animals.
About 100 million years ago , during the heyday of the dinosaurs, reefs were built by mollusks called rudist clams. Like modern clams, rudists were bivalves , with two shells (or valves) joined at a...
The Ottoia prolifica has proven that cannibalism did exist in the Cambrian period since there have been portions of one Ottoia prolifica found in another specimen’s gut.
During the late Cretaceous period, Kansas was covered by a vast sea. There, scientists have found fossils of Squalicorax sharks (also called crow sharks) that lived 70-80 million years ago. They were...
These deep-sea sediment cores were drilled from beneath the seafloor, and hold information about millions of years of ocean and atmospheric chemistry. As dirt, dead organisms, and other particles...
Most people have never heard of the Hawaiian petrel , an endangered, crow-sized seabird that spends the majority of its life searching for food over the North Pacific Ocean. Nevertheless, this bird...
Not all fossils from the Cambrian period became amulets; instead the extinct Hallucigenia sparsa was notable for its spines.
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...
Globotruncana falsostuarti -- a foram that lived about 75 million years ago, during the Cretaceous Period, from southeastern Tanzania. By measuring the chemistry in the shell, scientists can estimate...
Offshore Peru, during the Eocene (~56-34 million years ago), showing three archaeocetes (ancient whales), along with a previously described fossil penguin. Top to bottom: Perudyptes devriesi ,...
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...
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...
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