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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...
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What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is the...
About 100 million years ago , during the heyday of the dinosaurs, reefs were...
For a long time, scientists thought that some small tentacled fossils were...

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

The Ocean Blog

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...
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...
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.
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...
Humans are late arrivals on Earth. For nearly 75% of Earth’s history, life consisted of single-celled microbes without a nucleus (prokaryotes). Volcanoes and erosion sculpted Earth 3.5 billion years...
Crinoids (echinoderms related to sea stars and sea urchins) dominate the Paleozoic shallow water habitat in this illustration. They evolved a variety of stalk heights, which enabled them to capture...
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—...
Hantkenina mexicana -- a foram with elongated shell chambers that lived between 45-49 million years ago, during the Eocene Epoch. This specimen is from marine sediments that were drilled in the...
An archaeologist arranges a deep-sea core from off the coast of Britain. These cores are long cylinders of the earth's crust, drilled up from beneath the seafloor. When the cores shown here are...
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...
The Haplophrentis carinatus had two oar-like appendages (called “helens”) used to stabilize the creature and help it move along the ocean bottom.
Opabinia was a strange looking creature: it had five mushroom-like eyes that allowed it to see predators approaching from many directions.
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.
Not all fossils from the Cambrian period became amulets; instead the extinct Hallucigenia sparsa was notable for its spines.
This illustration shows one old idea of what the ancient shark Helicoprion might have looked like. There once was room for many ideas—some more plausible than others—because the only fossils of the...
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...
The Wiwaxia corrugata may have molted its scales in order to grow past these hard boundaries.
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...
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