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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...

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Lenticulina secans -- this foram lives on the seafloor. This specimen was collected from ocean sediments in southeast Tanzania. It comes from a time over 92 million years ago when both the polar...
This rendering shows life at the end of the Cretaceous Period, before the impact of a 6.2 mi (10 km) asteroid triggered mass extinctions on land and sea. Dinosaurs are the most famous victims of 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...
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...
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...
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.
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...
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...
The great predator Hurdia victoria’s prey consisted of trilobites and other smaller animals crawling on the seafloor.
This early whale was well suited to life at sea. But it also lived on land. An ancestor of the right whale , Maiacetus lived 49-40 million years ago. It had flipper-like limbs and webbed feet, like...
Opabinia was a strange looking creature: it had five mushroom-like eyes that allowed it to see predators approaching from many directions.
Fossils from the Cambrian period are found throughout the world. The Chengjiang fossil site in china is famous for containing about 196 species of fossils, many from the Cambrian period. The Burgess...
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 whales that we see in today's world can broadly be split into two groups: those with teeth (odontocetes), and those that have baleen (mysticetes) instead of teeth. These two groups share a common...
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...
Today, filter feeders like clams, sponges, krill, baleen whales, fishes, and many others fill the ocean, spending their days filtering and eating tiny particles from the water. But when did the first...
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...
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